
Class Be ^oj 

B()()k__lLi^_ 



PUKSKNTh:i) BY 



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ELEiMENTS VXI^O 



OF 



L G I C K. 

BY 

JOHN ANDREWS, D. D. 

LATE VICE-PROVOST 
OF THE UNIVERSITY OF PENNSYLVANIA. 



THE FIFTH EDITION. 



Quicquid prsecipies, esto brevis ; ut cito dicta 
Percipiant animi dociies, teneantque fidelts. 
Omne supervacuum pleno de pectore manat. 



PHILADELPHIA : 

PRINTED AND PUBLISHED BY R. H. SMALL, 

No. 165, Chesnut Street. 

1835. 






7;- 



District of Pennsylvania j to wit : 

BE IT REMEMBERED, That on the seco-.id day of December, in 

^^^^ the Ihirty-second year of the Independence of ihe U ited 

L.S. States of America, A. D- 1807, Benjamin B. Hopkins, & Co. 

^^^ of the said disirict, have deposited in this Office the Title of a 

Book, the right whereof the) claim as Proprietors, in (he words 

following to wit : 

" Elements of Logick. By John Andreiv^, I). D Vice-Provost of 
the University of Pennsylvania. The second edition, -with corrections 
and additio7is. 

Quicgnid prcecipies. esto brevis ; ut cito dicta 

Percipiaut animi dociles, teneantque fdeles . 

Omne mipervacinL7n pleno de pectore manat.'^^ * 
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and etching historical and other prints." 

D. CALDWELL, 
Clerk of the District of Pennsylvania. 



q;^ The above Copy Right has been purchased by Abraham Smaix, 
and IS regularly transferred to him. 



^^4.^0. «^//f 3a 



PREFACE. 



OF the few treatises of Logick which 
the author of the following compilation has 
perused, Duncan's has always appeared to 
him to be the best. But this treatise, how- 
ever excellent, is for the most part too dif- 
fusive, and in some places, perhaps, even 
too scientific, for the use of young begin- 
ners; at the same time that it omits a num- 
ber of particulars, of which (as they are 
generally taught in the schools, and occa- 
sionally alluded to in conversation as well 
as books) a teacher would not wish his pu- 
pils to be wholly ignorant. To obviate 



these objections, and yet retain as much as 
possible the features of Duncan, is the aim 
of the present compend ; which was com- 
posed some years ago, and is now printed, 
that the classes, for whose use it was inten- 
ded, may no longer have the trouble of 
transcribing it. 




ELEMENTS 



OF 



L O G I C K. 



liOGicK is that science which explains 
the operations of the human understanding, 
in acquiring and communicating knowledge. 
And as these have been usually stated to 
be four, — apprehending, judging, rea- 
soning, and ARRANGING OUR THOUGHTS in 

a suitable manner; so Logick, which treats 
of these operations, is usuallj^ divided into 
four parts. 

B 



PART I. 



Of Simple ,S.pprehension. J 

Simple apprehension being that opera- 
tion of the mind by which it is furnished 
with ideas, a treatise on it, is, in a great mea- 
sure, a treatise on ideas, and on the. proce- 
dure of the mind with respect to them : and it 
is also a treatise on words and definitions; 
because, without these, we should often be at 
a loss both in acquiring and communicating 
our ideas. The first part, therefore, of Lo- 
gick, may be divided into two chapters : one, 
treating of ideas ; and the other, of terms and 
definitions. 



4 



CHAPTER 1. 



Of simple Apprehension , and the faculties; 
by lahich it is exerted. — Of Ideas, or the 
first principles of knowledge. — Of the 
sources from which they are derived ^ and 
of the different sorts of them. 



Simple Apprehension is that operation 
of the understanding by which it attends to^ 
and notices, the several objects that are pre- 
sented to it. It is called simple apprehension; 
because it is employed in the mere apprehend- 
ing or noticing of things ; w ithout comparing 
them with each other, or assigning to them 
any attributes ; which is the province of 
judgment. And by this operation it is, that 
the mind, as we have already observed, is 



8 

furnished with ideas : for without previously 
attending to, and noticing, the objects that 
are presented to it, it is impossible that the 
mind should ever have any ideas of them ; 
or, in other words, be able to re[)resent 
to itself the appearances which they ex- 
hibit. 

In performing this operation, two facul- 
ties are made use of, which are quite dis- 
tinct from each other ; sensation, and con- 
sciousness. If the object occurring be an 
external thing, the mind perceives it, and 
its qualities, by means of the senses ; and 
the power of doing this is called the fa- 
CULTY OF SENSATION : if it be an internal 
thing, that is, if it be any operation or emo- 
tion of the mind, the mind attends to and 
notices it, without making use, so far as we 
know, of any bodily organ : and it is this 
powder, which we call the faculty of con- 
sciousness. 



9 

The term Idea is derived from the Greek 
word E/cT^, I see : and by ideas are meant, the 
views which the mind takes of things, when 
they are no longer present. In the language 
of the schools, ideas are the types or resem- 
blances of things ; and things themselves are 
the archetypes, or originals of which the re- 
semblances are made. When an external 
object is present, and attended to by my mind, 
I am said to perceive it; and when my mind 
is engaged in any operation, or agitated by 
any passion or emotion, I am said to be con- 
scious of that operation, or of that passion 
or emotion: but when the external object is 
no longer present, so as to affect the organs 
of sense, or when the operation which had 
engaged my mind ha« ceased to engage it, or 
the passion or emotion, by which 1 was a«*i. 
tated, now agitates me no more, I am capable 
of thinking of the object which I before per- 
ceived, or of the operation or emotion of which 
B3 



10 

J was conscious, and of representing to my- 
self the appearances which they respectively 
exhibited ; and when I do so, I am said to 
have IDEAS of them. 

It has been stated^ that all external 
things and their qualities are noticed by 
means of the senses: and internal things, 
that is, the operations and emotions of the 
mind, by consciousness : now all the objects 
of which we have any knowledge, are either 
external things and their qualities, or the 
operations and emotions of the mind : and, 
consequently, all our ideas, how numerous 
soever they may be, are derived from these 
two sources. 

As ideas are the first elements of all our 
knowledge ; so sensation and consciousness 
are the first of our intellectual faculties 
which are exerted by us. And as we can 
have no ideas of the operations of our 



11 

minds until these operations are exerted ; 
and as they cannot be exerted, before the 
Uiind is furnished with ideas of external 
things about which to employ them ; the 
ideas which give the first employment to 
our faculties, are evidently the ideas of ex- 
ternal things, communicated by the stnses : 
whence it is plain, that all our linowledge 
must begin in sensation ; and that the opera- 
tion of this faculty is prior even to that of 
consciousness. 

Ideas are either simple or complex. 
A simple idea is an idea of a simple object ; 
that is, an object without parts ; or it may 
be defined, an idea which cannot be resolv- 
ed into two or more ideas. A complex idea 
is an idea of a complex object; that is, of 
an object that consists of parts : or, it is aa 
idea, that may be resolved into two or more 
ideas. 



13 

To the former of these classes belong 
all our ideas of qualities, and of the opera- 
tions and emotions of our own minds. The 
qualities of external things are called sensl 
BLE QUALITIES ; and may be reduced to five 
general heads, according to the several 
senses which are affected by them. Light 
and colours are perceived by the eye : 
sounds, by the ear : tastes, by the tongue ; 
smells, by the nose; and heat and cold, 
roughness and smoothness, hardness and 
softness, &c. by the touch. Extension, 
figure, rest, and motion, we perceive by two 
senses ; seeing, and feeling. To which 
may be added, that our ideas of pleasure 
and pain, of power, existence, unity, and 
succession, are conveyed into our under- 
standings both by sensation and conscious- 
ness ; that is, both by the action of objects 
around us, and the consciousness of what we 
feel within. Other qualities are l^TKLLEC. 

TUAL, MORAL, &C. 



13 

To this general view of our simple 
ideas may be sulyoined the two following 
observations. The first is, that simple 
ideas can only he conveyed into the mind 
by the proper channels and avenues pro- 
vided by nature ; insomuch that if we are 
destitute of any of those inlets^ all the ideas, 
thence arising, are absolutely lost to us; nor 
can we, by any quickness of understanding, 
find a remedy for this want. A man born 
blind is incapable of ideas of light and co- 
lours ; as one, w ho is born deaf, can form 
no conception of sounds. And hence it 
appears, that these our simple ideas are just 
such as nature furnishes them, and have no 
dependence on our will : we can neither 
destroy them when in the understanding: 
nor fashion or invent any new one, not 
taken in by the ordinary means of appre- 
hension. So that the utmost bounds of hu- 
man knowledge cannot exceed the limits of 
our simple ideas and their various combina^ 



11 

tions. The second is, that though the mind, 
in multiplying its conceptions, can avail it- 
seir of no other materials than those which 
are furnished by sensation and conscious- 
ness : yet. as it has a power of combining 
these materials in a great variety of ways, 
it finds itself in possession of an inexhaus- 
tible treasure of ideas, sufficient to employ 
it to the full extent of its powers. 

Complex ideas arc of two sorts : those 

WHICH ARE CONVEYED INTO THE MIND BY 
THINGS REALLY EXISTING IN NATURE ; AND 
THOSE WHICH ARE THE WORKMANSHIP OF 
THE MIND ITSELF. 

Things really existing in nature are all 
comprised under the general name of sub- 
stances ; w hich are either material or im- 
material. And the usual definition of a sul>- 
stance is, that it is a thing which subsists of 
itself^ without dependence upon any created 



15 

beings and is the subject of modes. ^ The 
idea, for example, of a material substance 
includes in it the idea of a thing subsisting 
of itself; and the ideas of its qualities, by 
which only, as we find by experience, it is 
made known to us: the idea of an immate- 
rial substance, in like manner, includes the 
idea of a thing subsisting of itself; and the 
ideas of its operations^ by which only, as 
we also find by experience, it is made known 
to ns. And hence it appears that it is nqt 
without reason, that all our ideas of sub- 
stances are considered as complex ideas. 

Modes are divided into essential and 
ACCIDENTAL. An essential mode is that 
which cannot be separated from its subject^ 
without destroying the nature of the sub- 
ject : an accidental mode is that which mav 



That is, of qualities or attributes* 



16 

be separated from its subject, and the nature 
of its subject remain the same as it was be- 
fore. Roundness, for example, is an essen- 
tial mode of a ball ; because a thing cannot 
be a ball without being round ; but any par- 
ticular colour is an accidental mode of a 
ball; because if a ball, which is now blue, ' 
were to be painted white, it would still be a 
ball as much as ever. 

Essential modes are divided into pri- 
mary aind SECONDARY. A primary essen- 
tial mode is that which is derived from no 
other mode, and constitutes a thing what it 
is. A secondary essential mode is that, 
which, although inseparable from its sub- 
ject, is derived from some other mode. 
Thus roundness is a primary essential 
mode of a ball ; because we do not conceive 
of it as derived from any other quality of a 
ball ; but volubility, or aptness to roll, 73 a 
secondary essential mode of a ball-; because 



17 

it arises from another quality of it, that is, 
its roundness. The primary essential mode 
has been called differentia, or the differ^ 
ence; the secondary essential mode, pro- 
FRiuM, or a property 5 and the accidental 
mode^ ACCiDENS. 

Complex ideas, which are the workman- 
ship of the mind, are divided into com- 

POUND — UNIVERSAL, GENERAL, or ABSTRACT 
— and RELATIVE. 

Compound ideas are those, which the 
mind forms by putting two or more ideas to- 
gether. These combinations are sometimes 
made by adding the same idea to itself : 
thus, by adding the idea of unity to itself re- 
peatedly, and retaining the several amountis 
in our minds, we come by all the different 
combinations of numbers : in the same way 
are formed the different ideas of yards, 
perches, furlongs, miles, leagues, &c ; also 

C 



18 

those of weeks, months, years, &c. But, 
more frequently, our compound ideas are 
formed by combining ideas of a different 
kind together. The composer of music, 
for example, forms the idea of a tune which 
he is composing, and the mechanic, the 
idea of a machine which he is projecting, — 
by bringing together, in the former case, a 
number of notes — and, in the latter, of parts 
that are diflferent from each other. 

An abstract, universal, or, as it is more 
commonly called, a general idea, is an idea 
that will apply to several individuals, or to 
several classes of individuals. If it apply 
to individuals only, the class which corres- 
ponds to it, and comprehends individuals, 
is termed a species; if to several classes 
of individuals, the class which corresponds 
to it, and comprehends these several 
classes of individuals, is termed a genus. 
The formation of these ideas depends on a 



19 

power which the mind possesses of remov- 
ing, from its idea of any object, what is pe- 
culiar to that object ; from its idea of an 
individual, whatever is peculiar to that iu- 
dividual ; and from its idea of a species, 
whatever is peculiar to that species : a pow- 
er, which^ by the writers on the human 
mind, is called the faculty of abstrac- 
tion. And hence it appears, that it is not 
without reason, that our general ideas are 
ranked among those which are the work- 
manship of the mind, and have nothing in 
nature to which they correspond. 

But that this may be better understood, 
it will be worth while to take a more dis- 
tinct view of the process of the understand- 
ing in tlie formation of these ideas. All the 
things in nature are individual things : that 
is, every thing is itself, and one ; and not 
another, and more that one. But when we 
come to take a view of the several indivi- 



20 

duals^ and observe that a number of them 
resemble each other in one or more particu- 
lars of importance, selecting the particulars 
in which they agree, and removing all those 
in which they disagree, we frame to our- 
selves a general idea applicable to several 
individuals ; that is, to a particular species. 
Thus certain animals being found to resem- 
ble each other in having an erect form, and 
in being endowed with the faculties of rea- 
son and speech, we take these important 
particulars which are common to them all, 
and excluding what is peculiar to each, we 
form a general idea, to which we give the 
name of man ; and this name belongs equal- 
ly to every individual who is possessed of 
the form and faculties above mentioned. 
This is the first step or gradation in the 
forming of abstract ideas, when the mind 
confines itself to the consideration of indi- 
viduals, and frames an idea that compre- 
liends such only under it. 



31 

Again : having ranged things into spe- 
cies, according to the resemblance found 
among them, we begin to compare the se- 
veral species with each other; and often 
observe^ in these also, a resemblance^, in one 
or more particulars of importance. Upon 
this, throwing out all the particulars in 
which they disagree, and retaining those 
only, in which there is a resemblance, we 
frame a still more general idea, compre- 
hending under it several species. Thus^ 
a sparrow, a hawk, an eagle, &c. are dis- 
tinct species of birds : they nevertheless re- 
semble each other in being cov^ered with 
feathers, and provided with wings which 
bear them through the air: out of these 
particulars we form a new idea, and appro- 
priating to it the name bird^ mark by that 
word a higher class, which comprehends in 
it all the former This higher class, which 
extends to several species of things, is 
called a genus; and is the second step 



which the mind takes in the formation of its 
general ideas. 

But, in rising from particulars to gene- 
rals, the mind does nt)t confine itself to one 
or two gradations. For when we have re- 
duced things into species, and these again 
into genera, these genera are often found to 
resemble each other in some particulars, 
which being combined together into one 
idea, includes a new and more comprehen- 
sive cUss of things. Thus bird is a genus, 
comprehending the several species of spar- 
row, hawk, eagle, &c. : fish is a genus, in- 
cluding the several species of living crea- 
tures which inhabit the waters, as dolphins, 
sturgeons, &c. : beast or quadruped, and in- 
sect, are also genera, which extend to many 
species: yet all these diflFerent genera have 
this in common, that they are provided with 
organical bodies filled for the purposes of 
life and spontaneous motion. An idea, 



33 

therefore made up of these particulars only, 
will comprehend all the genera above men- 
tioned ; and the word, animal, by which it 
is expressed, denotes a higher genus, in- 
cluding the several creatures endued with 
life, sense, and spontaneous motion. 

Further : all things, animate and inani- 
mate, resemble each other in this respect, 
that they are created ; whence we refer 
them to a genus still higher, which may be 
called creature: a name, which belongs 
equally to every genus and species of cre- 
ated things, and to each individual thing 
that is created. 

And further still : all things, whatever, 
exist, or are ; and in this respect are said to 
resemble each other; in which view we 
refer them to a genus still higher, called 
Beings which is the highest possible genus. 



2i 

In a series of genera, rising in this 
manner one above another^, each successive 
genus is called-in the schools, a genus 

GENRRALtUS, Or HIGHER GENUS J aud the 

genus by which each series is terminated, 
they distinguish by the name of genus 
GENERALissiMUM. lu like manner, the se- 
veral genera, comprehended under a higher 
genus, are, in re^spect to it, considered as 
species ; and as these have also species 
under them, the inferior divisions, are, for 
the sake of distinction termed species 
SPECIALIORES, or LOWER SPECIES, And the 

lowest subdivisions of all, comprehending 
It 

only individuals, (which, as has been al- 
ready mentioned, constitute the proper s|)e- 
cies) are, in respect to the series, denomi- 
nated the SPECIES SPECIALISSIM^. All that 

lie between these and the hi2;hest distribution 
of things, or genus generalissimura, are the 

INTERMEDIATE GENERA AND SPECIES ; which 



25 

are termed successively genus generalius, 
or species specialior, according as we con- 
sider them in the ascending, or descending 
series of our ideas; or, to speak in the 
language of logicians, according to their 
ascent, or descent, in the linea prcedica- 
mentali. 

And here we may take occasion to men- 
tioQ merely, that, by the ancient writers of 
logick, a genus generalissiraum, with all its 
divisions and subdivisions, was termed a 
CATEGORY, or PREDICAMENT. Abd as Aris- 
totle fancied, that all things in nature might 
be reduced to ten general heads, or classes, 
namely, substance, quantity, quality, rela- 
tion, action, passion, place, time, situation, 
and clothing; these have been called the 

TEN CATEGORIES. 

It is of more importance to remark, 
that, though many of our general ideas are 



^6 

evidently combinations of different simple 
ideas, and in that view of them are included 
in the class of compound ideas, we are 
carefully to distinguish between an idea as 
it is compound^ and as it is general or uni- 
versal. 

An idea is termed compound, with re- 
spect to the several ideas which are com- 
bined in it ; general or universal, with re- 
spect to the individuals, species, or genera, 
to which it extends. Thus, the idea of a 
bird, considered as a compound idea, in- 
eludes life, sense, spontaneous motion, a cov- 
ering of wings, feathers, &c. : but, as a ge- 
nevaX idea, it denotes the several species of 
the feathered creation, the hawk, the eagle, 
the lark, &c. ; to all which it extends with 
equal propriety. In the former case, the 
several parts of the compound idea are 
called its compkehension ; in the latter, 
the genera, the species, and the individuals. 



37 

to which the universal idea may be applied 
are called its extension. 

The third and last division, of those 
complex ideas which are the workmanship 
of the mind, consists of our relative ideas. 
A relative idea, is an idea which arises 
from the comparing of things, one with an- 
other, and observing (heir corre*>pondencies. 
For the mind is not limited to the consi- 
deration of objects, as they are in them- 
selves merely: but can examine them as 
connected with other things brought into 
view at the same time. And when it does 
so, and thence acquires new ideas, the ideas 
thus acquired are called relative ideas; 
and make, as is supposed, the largest class 
of our ideas. For every single object will 
admit of almost innumerable comparisons 
WHh others, and, in this way, may become 
a very pleoiiful source of ideas to the un- 
^lerstanding. Thus, if we compare one 



28 

thing with auother in respect to bulk, we 
get the idea of greater and less, or of equa- 
lity : if, in respect of time, of older and 
younger : ViwA so of other relations, which 
we can pursue at pleasure, and almost with- 
out end. 

So much, with respect to ideas ; which 
are the subject of the first chapter. We 
have stated, that all our simple ideas are 
conveyed into the understanding either by 
sensation or consciousness ; and are the ma- 
terials out of which all others are formed : 
that the mind, though it has no power over 
these, either to fashion or to destroy tliem, 
can yet combine them in an infinite number 
of ways ; and that from their various com- 
binations result all our complex ideas : that 
these complex ideas are of two principal 
kinds; first, such as are derived from with- 
out, and represent those combinations of 
simple ideas that have a real existence in 



29 

nature, — of which sort are all our ideas of 
substances ; secondly, such as are formed 
by the mind itself, arbitrarily uniting and 
putting together its ideas : and that, as these 
last make by far the largest class, and com- 
prehend all those ideas which may be pro- 
perly termed our own, as being the work- 
manship of the understanding : so they fall 
very naturally under three distinct heads* 
For either the mind combines several sim- 
pie ideas together in order to form them 
into one complex idea, in which the number 
and quality of the ideas united are princi- 
pally considered; in which way we become 
possessed of all our compound ideas : or it 
fixes upon any one of its ideas, whether it 
be a simple or compound idea, or an idea of 
a substance, and leaving out the circum- 
stances of time, place, real existence, and 
whatever reiiders it particular, considers 
what it has in common with other*?, and of 
that makes an idea which will apply to all 

D 



30 

of a kind ; whence our abstract or universal 
ideas are derived : or, lastly, it compares 
things one with another, examines their mu- 
tual connexions^ and thereby furnishes it- 
self with a new set of ideas, known by the 
name of relative ideas; which, as has been 
already remarked, make by no means the 
least important class of our ideas. 



.Jl 



CHAPTER II. 

Of Terms and Definitions. 

Having seen, in the preceding chapter, 
how our ideas are acquired ; let us now 
proceed to examine how they are communi- 
cated. Ideas themselves are not visible, 
nor can they be perceived by any outward 
sense. But God, designing us for society, 
and to have fellowship with those of our 
kind, has pro\ided us with organs fitted to 
frame articulate sounds, and given us also 
a capacity of using those sounds, or terms, 
as signs of ideas. Hence our ideas, which 
otherwise must have been locked up, as it 
were, in our own breasts, are brought forth 
and made to appear. For, any number of 



33 

meiHiaving agreed to make use of the same 
sounds as signs of the same ideas, it is 
evident^ that the repetition of these sounds 
must excite the same ideas in them all. 
When, for instance^ any train of ideas 
takes possession of my mind^ if the terms^ 
or sounds, by which I am wont to express 
them, have been annexed, by those with 
whom I converse, to the very same set of 
ideas^ nothing is more evident, than that by 
repeating those terras, according to the te- 
nour of my ideas, I shall raise in their 
minds the same train that has taken posses- 
sion of my own. Hence, by barely attend- 
ing to what passes within themselves, they 
will also become acquainted with the ideas 
in my understanding, and have them in a 
manner exposed to their viev/. 

So that we here clearly perceive how a 
man may communicate his sentiments to an- 
other, provided the language, in which he 



33 

converses, be copious enough to contain 
words, appropriated to all his ideas ; and 
provided the person to whom he speaks, is 
possessed of the same ideas which he ex- 
presses, and has been accustomed to con- 
nect them with the same terms. 

But as this is not always the case, and 
as we may often have occasion to communis 
cate to others a new idea, that is, an idea 
that has never yet entered their minds, and 
which consequently they cannot as yet have 
connected with any term ; it may be asked^ 
by what means it is possible that the com* 
munication of such an idea should be of* 
fee ted ? 

This appears to be a difficulty : and, to 
solve it, it will be necessary to observe, 
fir^t, that no worri can be to any man the 
si2;n of an dea, till that idea comes to have 
a real existence in his mind. For vvoids 



31 

being only so far intelligible, as they denote 
known ideas ; where they have none such 
to answer to them, there they are plainly 
sounds without signification, and of course 
convey no information. But no sooner are 
the ideas, to which they belong, produced 
in the understanding, than, finding it easy 
to connect them with the established words, 
we can join in any agreement of this kind 
made by others, and enjoy the benefit of 
their discoveries. The first thing, there- 
fore, to be considered, is^ how these ideas 
may be conveyed into the mind, that, they 
being there, we may learn to connect them 
ivith the appropriated sounds, and so be- 
come capable of understanding others when 
they make use of these sounds in laying 
open and communicating their thoughts. — 
Now, to comprehend distinctly how this 
may be done, it will be necessary to call to 
mind the before mentioned divisions of oup 
ideas into simple aad complex. And first; 



35 



as to our simple ideas, it has been already 
obseived, that they can find no admission 
into the niitul, but by the origiual fountains 
of knowledge, sensation, and consciousness. 
If therefore any of these ha- e as yet no 
being in the understanding, it will be im- 
possible by wonis to excite them there. A 
man, who had never felt the impression of 
heat, conld not be brought to comprehend 
that sensation, by any thing which we could 
say to explain it. If we would produce the 
idea in him, it mu«t be by applying the pro- 
per object to his senses, and bringing him 
within the influence of a hot body. When 
this is done, and experience has taught him 
the sensation, to which men have annexed 
the name keat^ this term may then become 
to him the sign of that idea; and he is 
thenceforth capable of understanding the 
meaning of the term ; which, before, all the 
words in tlie world would not have been 
sufiBcieut to convey into his mind. Tlie 



36 

case is the same with respect to light and 
colours : a man born blind, and by this mis- 
fortune destitute of the only conveyance for 
the ideas of these objects, can never be 
brought to understand the terms by which 
they are expressed. The reason is plain : 
they stand for ideas which have no exist- 
ence in bis mind ; and as the organ, appro- 
priated to tlieir reception, i^ wanting, all 
other contrivances are vain, nor can these 
ideas, by any force of description, be excited 
in him. But, with our complex id<»as, it is 
quite otherwise. For, these being no other 
than certain combinations of simjile ideas 
put together in various forms, if the simple 
ideas, out of which the complex ideas are 
B)ade, have already got admission into the 
understanding, and the terms serving to ex- 
press them be known, it will be easy, by 
enumerating the several ideas included in 
the combination, and marking tlie order 
and manner in which they are united; to 



37 

raise any complex idea in the mind. Thus 
the idea answering to the terra, rainbow, 
may be readily excited in the imagination 
of another, who has never seen the appear- 
ance itself, by describing the figure, size, 
position, and order of colours ; if we sup- 
pose these several simple ideas, with their 
names, sufficiently known to him. 

The answer, then, to the question pro- 

posed above, is now sufficiently obvious 

If the new idea, which we wish to comma- 
nicate toothers, be a simple idea, there is 
no other way than to refer them to those 
objects in nature whence the idea is to be 
obtained : but, if it be a complex idea, its 
meaning may be explained by enumerating 
the ideas included in it; that is, by defin- 
iiig it. 

And here we see the nature and use of 
DEFINITIONS. They are used to unfold a 



38 

complex idea ; and two things are required 
in them : first, that all the simple ideas, out 
of which the complex one is formed, be dis- 
tinctly enumerated ; and secondly, that the 
order and manner of combining them be 
clearly explained. Where a definition has 
these requisites, nothing is wanting to its 
perfection; because every one who reads it, 
and understands the terms, seeing at once 
what ideas he is to join together, and also 
in what mannner, he can, at pleasure, form, 
in his own mind, the complex idea answer- 
ing to the term defined. 

But this rule, though it extends to all 
possible rases, and is indeed that alone to 
which we can have recourse where any 
dou! t or difficulty arises, it is not, however, 
necessary, or even expedient, to practise in 
every particular instance. Many of our 
ideas are extremely complex ; and, of 
course^ to enumerate all the simple ideas, 



39 

out of which they are formed, would he a 
very trouhlesome and tedious work. For 
which reason, loejicians have e.stahlished a 
certain compendious mode of defining; of 
which, it may not be amiss to give here a 
short account. If the thing to be defined 
be a species, they give the nearest genus 
aird the specific difference; or, in other 
words, they refer it to its nearest genus, 
and then add those circumstances that make 
the species^ which they are defining, to dif- 
fer from every other species belonging to 
that genus. For, as the idea of a genus is 
formed by dropping what is peculiar to tarh 
of the several species referred to it, and 
retaining those particulars which they all 
possess in common; so, on the other hand, 
by adding to the genus what is peculiar to 
any one of the species included in it, we 
form Hu adequate idea, and give a complete 
definition, of that species. In like manner, 
if the thing to be defined be an individual^ 



10 



the logical definition will consist of the 
SPECIES and the numerical difference ; 
or, in other words, of the species, and 
those particukrs that distinguish the indi- 
vidual which we are defining, from every 
other individual belonging to that species. 
For, as the idea of a species is formed by 
dropping what is peculiar to the several 
individuals referred to it, and retaining 
those particulars only which they possess 
in commun; so, by adding to the species 
■what is peculiar to any one of the indivi- 
duals included in it, we form an adequate 
idea, and give a complete definition, of that 
individual. 

We shall conclude with observing, that 
definitions have been distinguished into two 
kinds; the definition of thk name, and 
the definition of the thing. When the 
term to be defined, refers t.) the i«lea of the 
writer or speaker, aud the defiuiiion is dc- 



u 

signed to show what idea he connects with 
a certain term, it is a definition of the name. 
And such definitions are said to be arbitra- 
ry ; because, as words are not natural, but 
merely artificial, signs of ideas, every man 
is at liberty to annex to a term what idea 
he pleases. But where the reader, or hear- 
er, is supposed to know that a certain term 
is connected with a particular idea, and 
where the design of the definition is to un- 
fold that idea, that the nature of the thing 
of which it is the type or resemblance, may 
be fully understood, it is a definition of the 
thing. And such a definition is not arbi- 
trary : because the idea of any thing should 
be conformable to that thing; and the de- 
finition conformable to the idea. 



E 



*2 



PART II, 



Of Judgment. 



All our knowledge may be reduced to 
two heads: our ideas of things, and the 
judgments which we form with respect to 
them. Of our ideas, and of terms and de- ^ 
finitions by which they are communicated, 
we have already treated. We come now 
to speak of our judgments ; and of propo- 
siTiONS, by which they are communicated. 
And here it will be proper to consider, 
first, the several grounds of human judg- 
ment ; and, secondly, the different sorts of 
propositions* 



43 



CHAPTER L 

Of the GROUNDS of Human Judgment ^ oVf 
in other words^ of the different sorts 

OF EVIDENCE. 

Judgment is that operation of the mind 
by which we compare two or more ideas 
together, with a view to determine whether 
they agree or disagree. But although^ in 
every act of judgment^ it is necessary to 
bring two or more ideas together^ and place 
them, as it were, over against each other; 
yet, the mere comparing of two ideas toge- 
ther is not the evidence of their agreement 
or disagreement. What then, it may be 
asked, is this evidence ? Or rather, (as one 
sort of truth is supported by one sort of evi- 



44 

dence, and another by another), What are 
the different sorts of evidence ? 

To assist us in judging of this subject, 
it will be necessary to observe, that all the 
objects of the human understanding are, 
cither abstract notions of quantify and num- 
ber^ or things really existing. Of the re- 
lations of these abstract notions, all our 
knowledge is certain ; being founded on 
mathematical evidence. Of things really 
existing, we judge, either from our own ex- 
perience, or from the experience of other 
men. Judging of real existence from our 
own experience, we attain either certainty 
or probability. Our knowledge of real things 
is certain, when supported by the evidence 
of external sense, consciousness, and memo- 
ry ; and when from effects we infer causes. 
Our knowledge of real things is probable, 
when from facts whereof we have had ex- 
perience, we infer facts of the same, or a 



43 

similar kind, not experienced. Judging of 
real existence from the experience of other 
men, we have the evidence of their testimo- 
ny. And thus it appears, that all sorts of 
evidence, productive of real knowledge, may 
be reduced to seven. — 1- Mathematical evi^ 
dence. 3. The evidence of external sense. 
3. The evidence of consciousness. 4. The 
evidence of memory. 5. That evidence 
which we have, when from effects we infer 
causes^ 6. I'he evidence of testimony. 7» 
Probable evidence. 

Of MATHEMATICAL EVIDENCE there are 
two sorts : intuitive and demonstrative^-^ 
Mathematical evidence is intuitive, when^ 
from the very nature of the ideas compar* 
ed, it appears, at first view, that they must 
necessarily agree or disagree. MathematU 
cal demonstrative evidence is direct or in- 
direct. When a conclusion is inferred fromi 
principles which render it necessarily true^ 
E3 



46 

the demonstration is direct. When, by sup- 
posing a given proposition false, we are ne- 
cessarily led into an absurdity, it is called 
indirect, apagogical, or ducens in absur- 
dum. Now that must be true, which we 
cannot, without absurdity, suppose to be 
false. And therefore both sorts of demon- 
stration are equally good, because equally 
productive of absolute certainty. 

All mathematical proof is founded upon 
axioms, or self-evident propositions, the con- 
traries of which are inconceivable. And 
this sort of proof seems to be peculiar to the 
sciences that treat of quantity and number ; 
and therefore, in no other science is the ma- 
thematical method of proof to be expected. 
For, in the other sciences, in most of them 
at least, truth and its contrary are equally 
conceivable. That Julius C«sar died a na- 
taral death is as easy to be conceived, as 
4hat he was murdered in the senate- house. 



47 

I feel a hard body, I do not feel a hard 
body, I see a white colour, I do not see a 
white colour, are all equally conceivable; 
and yet may be either true or false accord- 
ing to circumstances. We may conceive 
that the sun, after setting to-night^ will ne- 
ver appear again, or that any particular 
man will never die : and, yet we consider 
death as what must inevitably happen to 
every man, and the rising of the sun to- 
morrow as so certain, that no rational being 
can doubt of it Though, therefore, the ma- 
thematical method of proof is to be found 
in the mathematical sciences only, yet satis- 
factory proof may be found in any other 
science : and is actually found, in every 
part of knowledge that deserves the name 
of science. 

The EVIDENCE OF EXTERNAL SENSE, DO 

less than mathematical evidence, produces 
absolute certainty j though in another way. 



48 

Our perception of external things is attend- 
ed with an ^irresistible belief, that they ex- 
ist, and are what they appear to be. When 
I see a man or a horse, I can no more doubt 
of his existence, than of my own ; and my 
own 1 believe with as full assurance as that 
two and two are four. The existence of 
body is a self-evident fact. It needs no 
proof; for to disbelieve or doubt of it, is 
impossible : and it admits of none ; because 
we know of nothing more evident to prove 
it by. ^' ' 

The EVIDENCE OF INETRNAL SENSE, Or 

CONSCIOUSNESS, docs also produce absolute 
certainty. That we have within us a think- 
ing and active principle, called a soul or 
mind ; which is the same thing to-day as it 
was yesterday; is conscious of its own 
thoughts ; and exercises a a at iety of facul- 
ties diflferent in their objects and manner 
of operation ; are all of them suggestions of 



49 

internal sense or consciousness, which we 
believe because we feel them to be true ; 
and which if we were not to believe, would 
bring on us the charge of irrationality. 

The EVIDENCE OF MEMORY docs also 
produce absolute certainty. A child be- 
lieves, without any doubt, that, what he re- 
members distinctly to have seen or heard, 
he really did see or hear. And he believes 
this, not because he has been told that he 
may safely trust his memory ; but because 
the law of his nature determines him, of his 
own accord, to believe his memory as well 
as his senses. Indeed if we were to dis- 
trust our memory, or treat it as a fallacious 
faculty, our senses would be of little use to 
us, and we should be incapable both of 
knowledge and experience, and also of rea- 
soning; for we cannot be satisfied with a 
proof, unless we remember the steps of it, 
and believe that on that remembrance we 



90 

may depeticK Thoughts remembered may 
decay through length of time, and at last 
vanish ; but, of an event or object, that part 
which we distinctly remember, we believe 
to have been real. We may forget the 
whole subject of a book, and yet remember 
and consequently believe, that we read it. 
We may forget the proofs of a proposition, 
and yet remember that it was formerly pro- 
ved to our satisfaction, and acquiesce in it 
accordingly. If in conceiving any event or 
object, we are uncertain whether we remem- 
ber or only imagine, belief is suspended and 
we remain in doubt ; but no sooner are we 
conscious that we remember, than belief 
instantly takes place ; and we say, I am 
certain it was so, for now I remember it 
distinctly. 

As to THE EVIDENCE THAT WE HAVE 
W^HEN FROM EFFECTS WE INFER CAUSES, 

we may observe, that the law of our nature 



51 

determines us to believe, that whatever he* 
gins to existj proceeds from some cause. 
If, on going home, I should find, on the 
table, a book, which I never saw before, 
it would occur to me as absolutely certain, 
that some cause had brought and some per- 
son m^de it. For if I were to be told, that 
nobody brought it, and that it never was 
made, I should, without hesitation, declare 
such a thing to be not only absurd but im- 
possible ; and there is not one rational be=^ 
ing who in this would refuse to concur with 
me. Even children think in this manner, 
and some are very inquisitive into the causes 
of things : a proof that it is not experience 
merely which leads us to infer the cause 
from the effect. If the book, which I sup» 
posed myself to find, contained wise obser- 
vations, and was well printed and bound, 
I mu t of necessity believe, that the author, 
printer, and binder, were possessed of wis^ 
dom and skill equal to the eiBFect produced. 



That being whom we believe to have pro- 
ceeded from no cause but the necessity of his 
own nature^ and to be self-existent, and 
on all other beings independent, we must 
also believe to have existed from eternity^ 
or, in other words, to have had no begin- 
ning. For if every thing that had a begin- 
ning, proceeded from some cause, that which 
proceeded from no cause, could have had no 
beginning. 

Probable evidence is of two sorts. — 
One is, when, from facts whereof we have 
had experience, we infer facts of the same 
kind not experienced. It is natural for us 
to think, that the course of things whereof 
we have had experience, and now have, 
will continue, unless we have positive rea- 
son to believe that it will be altered. This 
is the ground of many of those opinions 
whicli we account quite certain. That to- 
morrow the sun will rise, and the sea ebb 



53 

and flow ; tliat night will follow day, and 
spring succeed the winter ; and that all men 
will die ; are opinions amounting to certain- 
ty: and yet we cannot account for them 
otherwise than by saying, that such has been 
the course of nature hitherto, and we have 
no reason to believe that it will be altered. 
When judgments of this kind admit no 
doubt, as in the example given above, our 
conviction is called moral certainty. I 
am morally certain, that the sun will rise to» 
morrow, and set to- day, and that all men 
will die, &c. The instances of past experi- 
ence, on which these judgments are founded, 
are innumerable; and there is no mixture of 
contradictory instances which might lead us 
to expect a contrary event. But if the ex- 
periences, on which we ground our opinions 
of this sort, are but few in number, or mix- 
ed with contradictory experiences, in this 
case we do not consider the future event as 
morally certain; but only more or less pro« 

F 



54 



bable according to the greater or less sur- 
plus of favourable instances. The other 
sort of probable evidence, which is termed 
ANALOGICAL, is, when from facts whereof 
We have had experience, we infer facts of a 
similar kind not experienced ; or, in other 
words, when we expect similar events in 
similar circumstances. For example, we 
think it probable that the planets are inha- 
bited, they being in all respects so like our 
earth. The force of an argument from ana- 
logy is in proportion to the degree of like- 
ness, that there is between the case from 
which we argue, and the case to which we 
argue. In the example given, the case 
from which we argue, is the circumstance 
of this earth's being a planet, warmed and 
enlightened by the sun, and inhabited by 
many varieties of living creatures ; and the 
case to which we argue, is that of the other 
planets, which being in all other respects 
so similar to our earth, we think it highly 



probable that they must resemble it in this^ 
in being the habitation of percipient beings. 
A man who thinks, as Epicurus did, that 
they aro no bigger than they appear to his 
eye, can have no notion of their being inha- 
bited, because to him they must appear in 
every respect so unlike our earth. And if 
we were to argue with him, in order to bring 
him over to our opinion, we should begim 
by explaining to him those particulars^ 
wherein the earth and the other planets re- 
semble each other. As soon as he under- 
stands these par4;iculars as well as we, he 
will, of his own accord, admit the probabili^ 
ty of our opinion. 

Another and the last species of evidence^ 
upon which we are to remark in this place, 
is TESTIMONY. It is natural for a man to 
speak as he thinks ; and it is easy, like 
walking forward. One may walk back- 
ward, or sideways ; but it is uneasy, and a 



56 

sort of force upon nature : and the same 
thing is true of speaking one thing and ' 
thinking another. It is also natural for us 
to believe what others seriously tell us. 
We trust the word of a man of whose vera- 
city w^e have had experience ; but we also 
credit testimony previously to such experi- 
ence ; for children, who have the least expe- 
rience^ are the most credulous. It is from 
having had experience of the dishonesty of 
men, and of the moti\ es that tempt them to 
it, that we come to disbelieve or to distrust 
what they say. In general, when we doubt 
a man^s word, we have some reason for it. 
We think that what he says is incredible in 
itself; or, that there is some motive or 
temptation which inclines him in the pre- 
sent case to violate truth ; or, that he is not 
a competent judge of the matter in which he 
gives testimony ; or, lastly, we distrust him 
now, because we know him to have been a 
deceiver formerly. 



57 

Faith in testimony often rises to abso» 
lute certainty. Of places and persons we 
never saw, and of which we know nothing 
but from the testimony of others, we believe 
many things as firmly as we believe our 
own existence. This happens, when the 
testimonies of men concerning such places 
and persons, are so many, and so consistent, 
that it seems impossible they should be fic- 
titious. When a number of persons, not 
acting in concert, having no interest to dis- 
guise what is true, or to affirm what is 
false, and who are competent judges of 
what they testify, concur in making the 
same report, it would be accounted folly to 
disbelieve them, especially if what they tes- 
tify be credible in itself. Even when three, 
or when two witnesses, separately examin- 
ed, having had no opportunity to concert a 
plan beforehand, concur in the same decla- 
ration, we believe them, though we have had 
no experience of their veracity ; because we 
V2 



58 

know^ that in such a case their declara^ 
lions would not be consistent, if they were 
not true. In regard to an impossible thing, 
we should not believe our own senses, nor 
consequently human testimony. Miraculous 
facts, however^ are not to be ranked with 
impossibilities. To raise a dead man to 
life, to cure blindness with a touch, to re- 
move lameness, or a disease, by speaking a 
word, are miracles : but to divine power as 
easy, as to give life to an embryo, make the 
eye an organ of sight, or cause vegetation to 
revive in the spring. If it be asked, what 
evidence is sufficient to establish the truth of 
miraculous events such as these, we answer, 
that every event admits of a proof from hu- 
man testimony, which it is possible for a 
sufficient number of competent witnesses to 
see and to hear. 



59 



CHAPTER 11. 

Of Propositions^ and their Various Kinds. 

A PROPOSITION is a judgment of the 
mind expressed in words. Now as our 
judgments include at least two ideas, one of 
which is affirmed or denied of the other; so 
must a proposition have terms answering to 
these ideas. The idea^ of which we affirm 
or deny, and of course the term ex-ressing 
that idea, is called the subject of that pro- 
position. Th'^ idea affirmed or denied, as 
also the term answering to it, is called the 
PREDICATE. Thus, in the proposition, God 
is omnipotent^ — God is the subject, it being 
of him that we affirm omnipotence ; and 
omnipotent is the predicate, because we af- 



60 

firm the idea^ expressed by that word, to 
belong to God. And that word, in a pro- 
position, which connects the subject and pre- 
dicate together, is called the copula ; as in 
the above mentioned proposition, where is-^^s 
the copula, and signifies the agreement of 
the ideas of God and omnipotence. But if 
we mean to separate two ideas, then, be- 
sides the copula we must also use some par- 
tide of negation to express this repugnance. 
Of this kind, the proposition, Man is not 
perfect^ may serve as an example ; where 
the idea of perfection b iog intended to be 
separated from the idea of many the nega- 
tive particle not is inserted after the copula, 
to signify the disagreement between the sub- 
ject and the predicate. But although every 
proposition necessarily consists of these 
three p<irts, it is not alike necessary that 
they be all severally expressed in words; 
because the copula is often included in the 
term of the predicate, as when we say he 



61 

writes^ which imports the same as he is 
writing. And in the Latin language, a single 
word has often the force of a whole sen- 
tence ; where ambulat, for example, is the 
same as ille est ambulans ; amo^ as ego sum 
amans. 

Propositions are either affirmative or 

NEGATIVE^ UNIVERSAL or PARTICULAR, AB- 
SOLUTE or CONDITIONAL, SIMPLE Or COM- 
POUND, SELF-EVIDENT Or DEMONSTRABLE; 
SPECULATIVE Or PRACTICAL. 

An aflSrmative proposition connects the 
predicate with the subject; as, A stone is 
heavy: a negative separates them : as, God 
is not the author of evil. And as, in all 
cases, the predicate must either be connect- 
ed with the subject, or separated from it, it 
is evident that all propositions fall under 
these two divisions. 



6a 

An universal proposition is a proposition 
which has for its subject some general lerrn 
taken in its full extent; sa that tlie predicate 
agrees with all the individuals comprehend- 
ed under it, if it be a proper spec^ies, and 
with all the several species and their indi- 
viduals, if it be what is termed a genus. 
Thus, Ml animals have a power of begin- 
ning motion^ is an universal proposition ; 
animalsp the subject being a general term 
without any mark of limitation, and by con- 
sequence taken in its full extent : hence the 
power of beginning motion may be affirmed 
of all the several species of animals, as of 
quadrupeds, birds, insects, fishes, &e. ; and 
of all the individuals of which these differ- 
ent species consist, as of this hawk, that 
horse, and so on with respect to the rest. 
A particular proposition is one, which has, 
in like manner, some general term for its 
subject; but with a mark of limitation 



63 

added, to denote that the predicate agrees 
with some only of the individuais compre- 
hended under it, if it be a species ; or with 
one or more, not with all, of the species be- 
longing to it, if it be a genus. Thus, Some 
stones are heavier than iron — Some men 
have an uncommon share of prudence. 
Where the subject of a proposition is an in- 
dividual, it is called a singular proposi- 
tion. Of this nature are the follbwing. Sir 
Isaac JSTewton was the inventor of fluxions— - 
This book contains many useful truths. 
And such propositions, though more parti- 
cular than those which are generally called 
so, come under the same rule with univer- 
sals ; because, in them, the subject is takeu 
in its full extent. 

It has been already observed, that all 
propositions are either affirmative or nega- 
tive : it is equally evident, that, in both 
cases, they may be universal or particular. 



6t 

Hence arises that celebrated fourfold divi- 
sion of them, into universal affirmative, 

UNIVERSAL negative; PARTICULAR AFPIR- 
MATIVE, and PARTICULAR NEGATIVE. And, 

in forming syllo^^isms, it has become a cus- 
torn, in the schools, to make use of the four 
vowels, a, e, z, o, to denote these varieties : 
a, to denote an universal affirmative, as. Ml 
good men are esteemed ; e, an universal ne- 
gative, as JSTo man is infallible ; z, a parti- 
cular affirmative, as, Some men are wise; 
Oy a particular negative, as Some men are 
not honest.^ 

The distinction of propositions into uni- 
versal and particular, is called their quan- 
TiTY ; and into affirmative and negative, 
their quality* 



^ i6 Assent a, negat e, vei^mn generaliter ambce : 
^( Jsserit i, negat o, sed particulariter ambo.^^ 



m 

Absolute propositions are those iti which 
we affirm, that some property is inseparable 
from the idea of the subject; as, Lead is 
heavy. Conditional propositions are those 
in which the predicate is not necessarily 
connected with the subject, and can be af- 
firmed of it on some condition only, distinct 
from the idea of the subject ; as, if a stone 
be exposed to the rays of the sun^ it will 
contract a degree of heat. And here we 
are to observe, that all conditional proposi- 
tions consist of two distinct parts ; one ex- 
pressing the condition upon which the pre- 
dicate agrees or disagrees with the subject, 
as, in the example before us, // a stone be 
exposed to the rays of the sun ; the other, 
joining or disjoining said predicate and sub- 
jert, as, in the same example, It will con-^ 
tract a degree of heat. The first of these 
parts is called the antecedent; the second^ 
the consequent. 



66 

When a propositipn has but one subject 
and one predicate^ it admits of no subdivi- 
sion, and is said to be simple. When it 
has more than one subject, or more than one 
predicate ; or has several subjects and predi- 
cates ; it is said to be compound. If it have 
one subject and more than one predicate, or, 
vice versap one predicate and more than one 
subject, it may, in the one case, be resolved 
into as many simple propositions as there 
are predicates, and, in the other, into as 
many as there are subjects ; as will be obvi- 
ous from the following examples : The prac- 
tice of swearing in common conversation^ 
is absurd^ unmannerly^ and impious — JVei- 
ther kings nor people are exempt from 
death. Nor is it less evident, that if a pro- 
position consists of several subjects and pre- 
dicates, it may be resolved into as many 
simple propositions, as there are subjects 
and predicates. Compound propositions 



67 

are of two kinds ; copulative and disjunctive. 
A copulative proposition takes place, where 
the subjects and predicates are so joined 
together, that they raay be all severally af- 
firmed or denied of each other. Of this na- 
ture are the examples which have been just 
given. A disjunctive proposition compares 
several predicates with the same subject, 
and affirms that one of them necessarily be- 
longs to it, but without determining which ; 
aS;, l^his world either exists of itself ^ or is 
the work of some allivise and powerful 
cause. It is the nature of all propositions 
of this class, that, upon determining the par- 
ticular predicate, the re^t are of course to be 
removed; or, that if alj the predicates but 
one be removed, that one necessarily takes 
place: thus, in the example given ahuve^ if 
we allow the world to be the work of some 
wise and powerful cause, we of course deny 
it to he self-existent ; or, if we deny it to be 
self-existent, we must necessarily admit^ 



68 

that it was produced by some wise and 
powerful cause 

A proposition is self-evident, when^ 
without any investigation or proof, the truth 
of it is obvious at first view. When we 
affirm^ for instance, that a part of any thing 
is less than the whole^ or that men exists and 
other animals; whoever understands the 
terms made use of, perceives at the first 
view, the truth of what is asserted ; nor can 
he, by any efforts, bring himself to believe 
the contrary. A demonstrable proposition 
is one, the truth of which does not immedi- 
ately appear, but may be made to appear by 
means of other propositions more known 
and obvious, from which it follows as an 
unavoidable consequence. 

A speculative proposition affirms or de- 
nies some property of its subject^ as when it 
is affirmed; that the radii of a circle are all 



69 

equal. A practical proposition asserts that 
something may be done or effected : as, that 
a right line may he drawn from one point 
to another. And from this last distinction 
arises a fourfold division of mathematical 
propositions, into self-evident specula- 
tive, and self-evident practical; de- 
monstrable speculative, and demon- 
strable PRACTICAL. Self-evident specu- 
lative propositions are called axioms ; and 
self-evident practical propositions, postu- 
lates ; demonstrable speculative proposi^ 
tions, THEOREMS : and demonstrable prac- 
tical propositions/ problems. 



eg 



70 



PART III. 



Of Reasoning. 



The subject of this part of Logick is an 
exteniive one; and to discuss it fully would 
require much time. We shall content our- 
selves with explaining what is meant by 
reasoning, and giving some account of va- 
rious kinds of syllogisms, which are acts of 
reasoning expressed in words. To which 
we shall subjoin such of the sophisms, or 
false arguments^ as are the most remarka* 
We. 



71 



CHAPTER I. 



Of Reasonings and the Parts of which it 
consists. 



It has been already observed, that, in 
comparing two ideas together, it will some- 
times happen, that their agreement or dis- 
agreement cannot be immediately^ discern- 
ed. In such cases it becomes necessary to 
look out for some third idea, that will admit 
of being compared with them, severally : 
that is, first with one and then with the 
other: that, by such comparison, we may 
be enabled to see how far the ideas, with 



* That is, without some medium^ or proof. 



73 

which this third is compared, do, them- 
selves, agree or disa2;ree. For it is a self- 
evident truth, that, if two things agree with 
a thirds they must agree with each other, 
and that, if one of two things agree with 
a third n and the other disagree with it, they 
must disagree with each other. 

From what has been said, it appears^ 
that every act of reasoning necessarily in- 
cludes three disrinct judgments : two, ia 
which the ideas, the relations of which we 
want to discover, are severally compared 
with the middle idea: and a third, in which 
they are themselves connected or disjoined, 
according to the result of that comparison. 
Now, as our judgments, when put into 
words, are called propositions ; so our acts 
of reasoning, when expressed by words, 
are termed syllogisms. And hence it fol- 
lows, that as every act of reasoning implies 
three several judgments, so every syllogism 



' 73 

must include three distinct propositions. 
And when an act of reasoning is thus put 
into words, and appears in the form of a 
syllogism^ the intermediate idea made use 
of to discover the agreement or disagree- 
ment which we seek to investigate, is called 
the MIDDLE, TERM ; and the two ideas them- 
selves, with which this third is compared, 
go hy the name of extremes. 

But, as these things are best illustrated 
by examples, let us suppose, that we have 
set ourselves to enquire, whether men are 
accountable for their actions. As the rela- 
tion between the ideas of man and account-- 
ablenesSf comes not within the immediate 
view of the mind, our first care must be, to 
find out some third idea that will enable us 
to discover and trace it. A very small 
measure of reflection is sufficient to inform 
us, that no creature can be accountable for 
bis actions, unless we suppose him capable 



74 

of distinguishing those which are good from 
those which are bad ; that is, unless we sup- 
pose him possessed of reason. Nor is this 
alone sufficient. For what would it avail 
him to distinguish good from bad actions, 
if he had no freedom of choice, and could 
not pursue the one and avoid the other? 
Hence it becomes necessary to take in both 
these considerations in the present case. It 
is at the same time equally evident, that 
wherever there is this ability of distinguish- 
ing good from bad actions, and pursuing 
the one and avoiding the other, there also a 
creature is acconntal>le. We have then got 
a third idea, with which accountableness is 
inseparably connected, namel;^, the idea of 
a creature possessed of reason and liberty. 
Let us now take this third or middle idea, 
and compare it with the other idea in ques- 
tion, namely man ; and we all know by ex- 
perience, that it may be affirmed of him* 
Having thus, by means of the intermediate 



75 

idea, formed two several judgments, that 
man is possessed of reason and liberty^ and 
that reason and liberty imply accountable- 
ness ; a third obviously and necessarily fol- 
lows, naraelj^, that man is accountable for 
his actions. 

Here then we have a complete act of 
reasoning, in which, according to what has 
been already observed, there are three dis- 
tinct judgments ; two, that may be styled 
previous, in as much as they lead to the 
other, and arise from comparing the middle 
idea with the two ideas in question ; and a 
third, which is a consequence of these pre- 
vious acts, and flows from uniting the ex- 
treme ideas themselves. If now we put 
this act of rea*^oning into due form, it exhi- 
bits what Logicians call a syllogism, and 
runs thus : 

Every creature^ possessed of reason and 
liberty is accountable for his actions. 



76 

Man is a creature possessed of reason and 
liberty : 

Therefore man is accountable for his 
actions. 

Of these three propositions, the two 
first answer the two previous judgments, in 
an act of reasoning; and are called the 
PREMISES, because they are placed before 
the other : the third is termed the con- 
CLusiON ; as being gained in consequence 
of what was asserted in the premises. Jlan 
and accountableness are the extremes ; and 
a creature possessed of reason and liberty^ 
the middle term. 

We may also observe, that, as the con- 
elusion is made up of the extreme terms of 
the syllogism, so that extreme, which serves 
as the predicate of the conclusion, goes by 
the name of the major term ; and the other 
extreme, which makes the subject in the 



77 

same proposition, is called the minor term. 
And again, from this distinction between the 
extremes arises also a distinction between 
the premises, where these extremes are se- 
verally compared with the middle term ; 
that proposition which compares the major 
term, or the predicate of the conclusion, 
with the middle term, being called the 
MAJOR proposition ; the other, wherein the 
same middle term is compared with the sub- 
ject of the conclusion or minor term, being 
called THE MINOR PROPOSITION. To which 
may be added, that, when a syllogism is 
proposed in due form, the major proposition 
is always placed first, the minor next, and 
the conclusion last. 

These things premised, we may define 
reasoning to be, Jin act or operation of the 
mind, deducing some proposition^ the truth 
of which was before unknown^ from other 
previous ones that are either self-evident or 

H 



78 

such as have been fully proved and esta- 
hlished. These previous propositions, in a 
simple act of reasoning, are only two in 
number ; and, in order to afford an unques- 
tionable conclusion, must be intuitive propo- 
sitions. When they are not so, previous 
syllogisms are required : in which case rea- 
soning becomes a complicated act, taking in 
a variety of successive steps* If, for exam- 
ple, in the major of the syllogism given 
above, viz. Every creature possessed of 
reason and liberty is accountable for his ac- 
tions^ the connexion between the subject and 
predicate could not be perceived by the 
mere attention of the mind to the ideas 
themselves, ii is evident that this propsi- 
tion would no less require proof than the 
conclusion deduced from it. In this case, a 
new middle term must be sought for, to 
trace the connexion here supposed ; and 
this of course, furnishes another syllogism ; 
by which having established the proposition 



79 

in question, we are then, and not before, at 
liberty to use it in any succeeding act of 
reasoning; And should it so happen, that, in 
the second syllogism, there were still some 
previous proposition, the truth of which did 
not appear at first sight, we must then have 
recourse to a third syllogism, in order to lay 
open that truth to the mind ; because, so 
long as the premises remain uncertain, the 
conclusion, built upon them, must be so toOo 
And when, by conducting our thoughts in 
this manner, we at last arrive at some syllo- 
gism where the previous propositions are in* 
tuitive truths, the mind then rests in full se- 
curity ; as perceiving, that the several con- 
elusions, which it has passed through, stand 
upon the immoveable foundation of self-evi- 
dence, and when traced to their source, ter- 
minate in it. 

And here, if, after having thus unravel- 
led a demonstration, we take it the contrary 



80 

way, and observe how the mind, setting out 
with intuitive propositions, connects them 
together to form a conclusion ; how, by in- 
troducing this conclusion into another syl- 
logism, it still advances one step farther; 
and so proceeds, making every new disco- 
very subservient to future progress ; we 
shall then perceive clearly, that reasoning, 
in the highest exercise of that faculty, is no 
more than an orderly combination of those 
simple acts which we have already so fully 
explained. And we shall also perceive, 
that all the knowledge acquired by reason- 
ing, how far soever we may carry our disco- 
veries, is still built upon our intuitive judg- 
ments ; every discovery of human reasoning 
being the consequence of a syllogism, the 
premises of which are self-evident proposi- 
tions, or of a train of syllogisms, which, 
when traced to their source, always termi- 
nate in them 



81 



Men reason, either to rank things un- 
der those universal ideas to which they 
truly belong, or to ascribe to them their 
several attributes and properties in conse» 
quence of that distribution. 

!• One great end for which men reason^ 
is to rank things under those universal 
ideas to which they belong; or, in other 
words, to determine the genera and species 
of things. We have seen, in the first part 
of this treatise, how the mind proceeds in 
forming general ideas. We have also seen, 
in the second part, how, by means of these 
general ideas, we form universal proposi* 
tions. Now, as in universal propositioug^ 
we affirm some property of a genus or spe- 
H3 



82 

cies, it is plain, that we cannot apply this 
prop»-rty to particular olyects, till we have 
first determined whether they are compre- 
hended under that general idea of which the 
property is affirmed. Thus, there are cer- 
tain properties belonging to all even numbers, 
which nevertheless cannot be applied to any 
particular number, until we have first dis- 
covered it to be of the species expressed by 
that general name. Hence, reasoning be- 
gins by referring things to their several di- 
visions and classes in the scale of our ideas : 
and, as these divisions are all distinguished 
by peculiar names, we hereby learn to ap- 
ply the terms expressing general concep- 
tions, to such particular objects as come un- 
der our immediate observation. 

In order to arrive at these conclusions, 
by which the several olyects of perception 
are brought under general names, two things 
are manifestly necessary. First, that we 



83 

take a view of the idea itself denoted by 
that ^^eneral name, and carefully attend to 
the distinguishing marks which serve to 
characterise it. Secondly, that we compare 
this idea with the object under considera- 
tion, observing diligently wherein they 
agree or dijBFer. If the idea be found to 
correspond with the particular object, we 
then without hesitation apply the general 
name ; but, if no such correspondence ap- 
pear, the conclusion must necessarily take 
a contrary turn. Let us, for instance, take 
the number eighty and consider by v/hat 
steps we are led to pronounce it an even 
number. First, we call to mind the idea 
signified by the expression, an even num- 
ber ; namely, that it is a number divisible 
into two equal parts : we, then, compare 
this idea with the number eight ; and, find- 
ing them manifestly to agree, we see at once 
the necessity of admitting the conclusion. 



84 

These several judgments^ therefore, trans- 
ferred into language, and reduced to the form 
of a syllogism, appear thus : 

Every number that may be divided into 
two equal parts^ is an even number : 

The number eight may be divided into 
two equal parts : 

Therefore the number eight is an even 
number. 

It may be observed, indeed, that where 
the general idea, to which particular objects 
are referred, is very familiar to the mind, 
and frequently in view, this reference, and 
the application of the general name, seem 
to be made without any reasoning. When 
we see a horse in the fleld^, or a dog in the 
street, we readily apply the name of the 
species; habit, and a familiar acquaintance 
with the general idea, suggesting it instan- 



85 

taneously to the mind. We are not, how- 
ever, to imagine, on this account, that the 
understanding departs from the usual rules 
of just thinking. A frequent repetition of 
acts begets a habit; and habits are attended 
with a certain promptness of execution, that 
prevents our observing the several steps and 
gradations, by which any course of action is 
accomplished. But, in other instances, 
where we judge not by pre-contracted ha- 
bits; as when the general i^l^a is very com- 
plex, or less familiar to the mind ; we al- 
ways proceed according to the form of rea- 
soning established above. A goldsmith, 
for instance, who is in doubt as to any piece 
of metal, whether it be of the species called 
gold J first examines its properties ; and, then 
comparing them with the general idea sig- 
nified by that name, if he find a perfect cor- 
respondence, no longer hesitates under what 
class of metals to rank it. Now what is 
this, but following step by step those rules 



86 

of reasoning \vhich we have before laid 
down, as the standards by which to regu- 
late our thoughts in all conclusions of this 
kind? 

Nor let it be imagined, that our re- 
searches here/ because in appearance bound- 
ed to the imposing of general names upon 
particular objects, are therefore trivial and 
of little consequence. Some of the most 
considerable debates among mankind, and 
such too as nearly regard their lives, inter- 
est, and happiness, turn wholly on this ar- 
ticle. Of what importance, for instance, is 
it, in many cases, to decide aright whether 
an action is to be termed murder or man- 
slaughter? We see, no less than the lives 
and fortunes of men depend often upon these 
decisions. The reason is plain. Actions, 
when once referred to a general idea, draw 
after them all that may be aflBrmed of that 
idea ; insomuch, that the determining of the 



87 

species of actions, is the same with deter^ 
mining what proportion of praise or dis- 
praise, commendation or blame, &c., ought 
to follow them. For, as it is allowed that 
murder deserves death, by bringing any- 
particular action under the head of murder, 
we of course decide the punishment due 
to it. 

2. The other great aim which men 
have in view in their reasonings, is, the dis« 
covering and ascribing to things their seve=. 
ral attributes and properties. And here it 
will be necessary to distinguish between rea- 
soning, as it regards the sciences, and as it 
concerns common life. In the sciences, our 
reason is employed chiefly about universal 
truths, it being by them alone, that the 
bounds of human knowledge are enlarged. 
Hence the divisions of things into various 
classes, called genera and species. For 
these universal ideas being set up as the re 



88 

presentatives of many particular things, 
whatever is affirmed of them, may be also 
affirmed of all the individuals to which 
they belong, Murder^ for instance, is a 
general idea, representing a certain species 
of human actions. Reason tells us, that the 
punishment due to it is death. Hence every 
particular action coming under the idea of 
inurder^ has the punishment of death allot- 
ted to it. Here, then, we apply the general 
truth to some obvious instance, and this is 
what properly constitutes the reasoning of 
common life. For men in their ordinary 
transactions and intercourse one with the 
other, have for the most part to do only 
with particular^i objects. 

Hence it appears, that reasoning, as it 
regards common life, is no more than the 
ascribing of the general properties of things 
to those several objects with which we are 
immediately concerned, according as they 



89 

.re found to be of that particular division or 
class^ to which the properties belong. The 
steps by which we proceed are manifestly 
these. Firsts we refer the object under con- 
sideration to some general idea of class of 
things ; we then recollect the several attri- 
butes of that general idea ; and, lastly^ 
ascribe all those attributes to the present 
object. Thus^ in considering the character 
of Sempronius^ if we find it to be of the 
kind called virtuous ; when we at the same 
time reflect, that a virtuous character is 
deserving of esteem ; it naturally and obvious- 
ly follows, that Sempronius deserves esteem. 
These thoughts put into a syllogism, in or» 
der to exhibit the form of reasoning here re- 
quired, run thus : 

Every virtuous man is deserving of esteem: 
Sempronius is a virtuous man : 
Therefore^ Sempronius is deserving of es^ 
teem, 

I 



90 

From this syllogism it appears, that be- 
fore we affirm any thing of a particular ob- 
ject, that object must be referred to some 
general idea. Sempronius is pronounced 
worthy of esteem, only in consequence of 
his being a virtuous man, or coming under 
that general idea. Hence we see the neces- 
sary connexion of the various parts of rea- 
soning, and the dependence they have, one 
upon another. The determining of the ge- 
nera and species of things is an exercise of 
human reason ; and this exercise is the first 
in order and previous to the other, which 
consists in ascribing to them their powers, 
properties, and relations. But when we 
have taken this previous step, and brought 
particular objects under general names ; as 
the properties we ascribe to them are no 
other than those of the general ideau, it is 
plain, that, in order to a succeswjful progress 
in this part of knowledge, we must fho- 
roughly acquaint ourselves with the several 



91 

relations and attributes of these our general 
ideas. When this is done, the other part 
will be easy and require scarce any labour 
of thouglit, as being no more than an appli^ 
cation of the general form of reasoning re* 
presented in the foregoing syllogismo 



92 



CHAPTER II 

Of Syllogisms 

Syllogisms may be divided into single 
and COMPOUND. Single syllogisms are 
those which consist of three propositions^ 
and no more. Compound syllogisms are 
those which consist of more than three pro- 
positions^ and may be formed into two or 
more syllogisms. 

Of Single Syllogisms. 

Single syllogisms may be divided into 
several sorts ; of which the most important 
are simple or categokical, conditional^ 
and DISJUNCTIVE. 



93 

Those are properly called Simple, or 
Categorical, syllogisms, which are made up 
of three plain, simple, or categorical propo- 
sitions ; iQ which, the middle term is joined 
with one part of the question in the major 
proposition, and with the other in the minor. 

And here, to guard us against false iri« 
ferences, certain rules have been found ne* 
cessary, which depend on the four following 
axioms. 

1. Particular propositions are contained 
in universals, and may be inferred from 
them; but universals are not contained ia 
particulars, and cannot be inferred from 
them. 

S. In all universal propositions, the sub- 
ject is universal ; in all particular proposi« 
tions, the subject is particular, 
IS 



94 

3, In all aflBrmative propositions, the 
predicate has no greater extension than the 
subject; for its extension is restrained by 
the subject : and therefore it is always to be 
esteemed as a particular idea. It is by 
mere accident, if ever it be taken univer- 
sally ; and cannot happen, but in such uni- 
versal or singular propositions as are reci- 
procal.* 

4^. The predicate of a negative proposi- 
tion is always taken universally : for in its 
whole extension, it is denied of the subject. 
If we say, JSTo stone is vegetable^ we deny 
all sorts of vegetation concerning stones. 



* A proposition is said to be reciprocal, when 
the subject and the predicate may mutually in- 
terchange their places with preservation of the 
truth. 



95 

The rules are these : 

1. The middle term must not be taken 
twice particularly^ but once at least univer- 
sally. For if the middle term be taken for 
two different parts or kinds of the same uni- 
versal idea, then the subject of the conclu- 
sion, or minor extreme, is compared with 
one of these parts, and the predicate, or 
major extreme, with the other part^ and this 
will never show whether that subject and 
predicate agree or disas^ree ; for there will 
then be four distinct terms in the syllogism, 
and the two parts of the question, that is, 
the two extremes, will not be compared with 
the same third idea, 

2. The terms^ in the conclusion, must 
never be taken more universally than they 
are in the premises. The reason is deriv- 
ed from the first axiom, that generals can 
never be inferred from particulars. 



96 

3. .5 negative concliinon cannot be 
proved by two affirmative premises. For, 
when the two terms of the conclusion are 
united, or asjr^e with the middle term, it 
does not by any means follow that they dis- 
agree with one another. 

4. If one of the premises be negative^ 
the conclusion must be negative. For if the 
middle term be denied of either part of the 
conclusion, it may show that the terms of 
the conclusion disagree, but it can never 
show that they agree. 

5. If either of the premises be particu- 
lar^ the conclusion must be particular. 
This may be proved from the first axiom. 
These two last rules are sometimes united 
in this single sentence, The conclusion al- 
ways follows the weaker part of the premi- 
ses. For negatives and particulars are ac 



97 

counted inferior to affirmatives and univer- 
sals. 

6. From two negative premises ^ nothing 
can be concluded. For they separate the 
middle term both from the subject and the 
predicate of the conclusion ; and when two 
ideas disagree with a third, we cannot infer 
that they either agree or disagree with each 
other. 

7. From two particular premises^ no- 
thing can he concluded. This rule de- 
pends chiefly on the first axiom. 

In forming syllogisms, especially those 
of which we are now treating^ we make use 
of FIGURES and moods. By the Figure of a 
syllogism, is m^ant the peculiar way in 
which the middle term is connected with 
the extremes. By the Moods belonging to a 
figure^ are meant, the several ways in which 



98 

the propositions of one syllogism may differ 
from tiiose of another, belonging to the same 
figure, as to quantity and quality ; that is, as 
to their being universal or particular, affir^ 
mative or negative. 

Figures are usually reckoned three. In 
the. jirst^ the middle term is the subject of 
the major, and the predicate of the minor, 
proposition. In the second^ it is the predi- 
cate of both these propositions ; and, in the 
thirdp the subject.^ 

The moods, belonging to each of these 
figures, are signified by certain artificial 
words, in which the consonants are neglect- 
ed, and the vowel only regarded ; a, denot- 
ing, as was before observed, an universal 



Sub prccy primse; bis pro?, secundae; tertisc* 
bis sub. 



99 

affirmative ; e, an universal negative ; z, a 
particular affirmative ; and o^ a particular 
negative. And to assist the memory in re- 
taining these words, they are comprised in 
four Latin verses* 

Barbara^ Celarent^ Baviiy Ferio quoque, 

primse:^ 
CesarCf Camestres^ Festino^ JBaroco^ se- 

cundsB : 
Tertia, Darapti sibi vindicat atque Felap- 

ton J 
Adjungens Disamis^ JDatisi^ Bocardo^ Fe- 

rison. 

Bar- All wicked men are miserable : 

BA- Tyrants are wicked men : 

RA. Therefore tyrants are miserable. 



100 

Ce- No practice, inconsistent with the 
Christian law of charity^^ can be 
innocent. 

LA- The practice of reducing men, of any 
colour, to a state of slavery, is 
inconsistent with the Christian 
law of charity. 

RENT. Therefore the practice of reducing 
men, of any colour, to a state of 
slavery, cannot be innocent. 

Da- Whatsoever furthers our salvation 
is good for us : 

Bi- Some afflictions further our salva- 
tion : 

I. Therefore some afflictions are good 

for us. 



^ Wliatsoever ye would that men should do to 
you, do ye even so to them. — Matt. vii. 12. 



101 

Fe. JK'^otliing that must be repented of) 

is desirable : 
III- Sinful pleasures must be repented 

of-- 
o. Therefore sinful pleasures are not 

desirable. 

It is the excellence of this figure, that 
all questions may be proved by it, whether 
universal or particular, affirmative or nega- 
tive. 

In the second figure also, there are four 
moods ; but it admits of negative conclusions 
onlv. 



K 



102 

Ce. No one, who is either a good Chris- 
tian, or a good citizen, can delibe. 
rately resolve to do what the laws 
of God and his country forbid : 

SA- A duellist deliberately resolves to do 
what the laws of God and his coun- 
try forbid : 

BE. Therefore no duellist can be, either a 
good Christian, or a good citizen. 

Ca- Every man of strict honour would 
disdain to enrich himself at his 
neighbour's expense : 

MES- No gamester disdains to enrich him- 
self at his neighbom^^s expense : 

TRES. Therefore no gamester is a man of 
strict honour. 



103 

Fes- No sins are excusable : 

Ti- Anger, upon some occasions, is ex- 
cusable : 

NO. Therefore anger, upon some occa- 
sions, is not a sin. 

Bal- Every true patriot will seek to jpro- 
mote peace and concord among hi^ 
fellow citizens : 

KG- Some, who profess to be patriots, do 
not seek to promote concord and 
peace among their fellow -citizens. 

CO. Therefore some^ who profess to be 
patriots, are not true patriots. 

In the third figure, there are six moods | 
and the conclusion is always particular. 

Da- All good Christians shall be saved : 
^RAP- Jill good Christians have sinned : 
TTo Therefore some, who have sinned^ 
shall be saved 



104 

Fe- No hyiiocrites are jileasing to God : 
LAP- All hypocrites seem to be religious : 
TON. Therefore some, who seem to be re- 
ligious^ are not pleasing to God. 

Di- Some selfish and turbulent men make 
very violent pretensions to patri- 
otism : 

SA- All selfish and turbulent men are 
destitute of any real love for their 
country : 

MIS. Therefore some, who are destitute of 
any real love for their country, 
make very violent pretensions to 
patriotism. 



105 

Da- All honest men are entitled to our 
love and esteem : 

Ti- Some honest men differ very widely 
from us in their sentiments with 
resp(^ct to religion and politics : 

^i. Therefore some, who differ very 
widely from us in their sentiments 
v/ith respect to religion and poli- 
tics, are entitled to our love and 
esteem. 

Bo- Some wars d¥e not to be avoided : 
CAR. All tvars produce blood-shed : 
DO. Therefore some blood-shed is not to 
be avoided* 

Fe- No afflictions are pleasant : 
HI- Some afflictions are good for us : 
SON. Therefore some things, which are 
good for us, tne not pleasant. 

K2 



106 

The special rules of the three fi2;nres 
are these. In the first, the major proposi- 
tion must always he universaL and the mi- 
nor affirmative. In the second, the major 
must also be universal^ and one of the pre^ 
miiies^ together with the conclusion^ must he 
negative. — In the third, the minor must he 
affirmative^ and the conclusion always par- 
ticular. 

There is also a fourth; in which the 
middle terra is the predicate of the major 
proposition, and the subject of the minor. 
But this, being a very indirect and ohlique 
manner of concluding, is never used in the 
sciences, or in common life ; and is, conse- 
quently, useless. 

A Conditional or Hypothetical Syllogism 
is a syllogism of which the major is a con- 
ditional or hypothetical proposition ; as, 



107 

If there be a God he ought to be wor- 

shipped : 

But there is a God : 

Therefore he ought to be worshipped. 

And here it is * to be observed, that^ in 
all proposition'^ of this kind, the antecedent 
must alwayn contain some certain and ge- 
nuine condition, which necessarily implies 
the consequent ; for otherwise the proposi- 
tion itself will be false, and therefore ought 
not to be admitted into our reasonings. 
Hence it follows, that, when any condi- 
tional proposition is assumed, if we admit 
the antecedent of that proposition, we must 
at the same time necessarily admit the con- 
sequent; but that, if we reject the conse- 
quent, we must in like manner necessarily 
reject the antecedent. It appears then^ 
that; in conditional syllogisms, there 



lOS 

are two ways of arguing which lead to a 
certain and nnavoidahle conclusion, 1. 
From the admission of the antecedent, to 
the admission of the consequent : which con- 
stitutes the mood or species of h^pothetipal 
syllogisms, distinguished in the schools by 
the name of the modus ponens ; inasmuch 
as by it t^e whole cnnditional proposition is 
established. And, of this mood, the syllo- 
gism given above is an example, 3. From 
the removal of the consequent, to the remo- 
val of the antecedent: which constitutes the 
mood or speries called by Logicians the 
MODUS TOLLENS, b^cause by it both antece- 
dent and consoqunnt are rejected; as ap- 
pears by the following example. 

If the sun he risen, the night is past : 

But the night is not past: 

Therefore the sun is not risen. 



109 

These two species take in the whole 
class of conditional syllogisms, nd include 
all the possible ways of arguing which lead 
by them to a legitimate conclusion ; because 
we cannot here proceed by a contrary pro- 
cess of reasoning, that is, from the removal 
of the antecedent to the removal of the con- 
sequent, or from the establisliing of the con- 
sequent to the establishing of the antecedent. 
For although the antecedent always ex- 
presses some real condition, which once ad- 
mitted, necessarily implies the consequent, 
yet it does not follow that there is therefore 
no other condition ; and if so, then, after re- 
moving the antecedent^ the consequent may 
still hold, because of some other condition 
which implies it. When we say. If a stone 
be exposed for some time to the rays of the 
sun^ it will contract a degree of heat ; the 
proposition is certainly true, and admitting 
the antecedent we must admit the conse» 
quent. But^ as there are other ways by 



110 

which a stone may contract a degree of 
heat^ it will not follow^ from the absence 
of the before mentioned condition, that 
therefore the consequent cannot take place. 
In other words, we cannot argue, But this 
stone has not been exposed to the rays of the 
sun; therefore it has not contracted a degree 
of heat; inasmuch as there are other ways, 
by which lieat might have been contracted 
by it. And as we cannot argue from the 
removal of the antecedent to the removal 
of the consequent, no more can we argue 
from the adcoission of the consequent to the 
admission of the antecedent. Because, as 
the consequent may flow from a variety of 
causes, the allowin^^ of it does not deter- 
mine the precise cause, but only that there 
must have be^Mi some on* of them. Thus, 
in the foregoing proposition, If a stone be 
composed for some time to the rays of the sun^ 
it will contract a des^ree of heat. — admitting 
the consequent, namely, thatzi has contract 



Ill 

ed a degree of heatj we are not therefore 
bound to ad J lit the antecedent^ that it has 
for some time been exposed to the rays of 
the sun ; inasmuch as there are other causes 
whence that heat may have proreeded. 
Tiiese two ways, therefore, of arguing^ hold 
not in conditional syllogisms : except, in- 
deed, where the antecedent expresses the 
only condition; which is a case that hap- 
pens but seldom, and cannot be extended to 
a general rule. 

A disjunctive syllogism is a syllogism of 
which the major is a disjunctive proposition: 
as in the following example. 

The world is either self existent, or the 
work of some finite, or of some infinite being: 

But it is not self existent^ or the work of 
a finite being: 

Therefore it is the work of an infinite 
being. 



lis 

Now a disjunctive proposition is that, in 
which, of several predicates, we aflRrm one 
necessarily to belong to the subject, to the 
exclusion of all the rest; but leave that par- 
ticular one undetermined. Hence it fol- 
lows, that, as soon as we determine the par- 
ticular predicate, all the rest are of course 
to be rejected ; or if we reject all the predi- 
cates but one, that one necessarily takes 
pl^ce. When therefore, in a disjunctive 
syllogism, the several predicates are enu- 
merated in the major, if the minor establish- 
es any one of these predicates, the con ^- 
gion ought to remove all (he rest; or if in 
the minor, all the predicates but one are re- 
moved, the conclusion must necessarily es- 
tablish that one. Thus, in the disjunctive 
syllogism given above, the major affirms one 
of three predicates to belong to the world; 
namely, that it is self existent^ or that it is 
the wo7*k of a finite^ or that it is the work of 
an ivjinite being; two of thesf' predicates 



113 

are removed in the minor ; namely^ self- 
existence^ and the work of a finite being: 
hence the conclusion necessarily ascribes to 
it the third predicate, and affirms that it is 
the work of an infinite being. If now we 
give the syllogism another turn, so that the 
minor mn,y establish one of the predicates, 
by affirming the world to be the production 
of an infinite being; then the conclusion 
must remove ^he other two ; by affirming it 
to be neither self existent^ nor the work of 
a finite being. These are the forms of rea- 
soning in this species of syUogisms ; the 
justness of which appears at first sight; and 
that there can be no other, is evident from 
the very nature of a disjunctive proposition. 



114 



In the several kinds of syllogisms hi- 
therto lueotioned, the parts, it may be ob- 
served, have always been complete ; that is, 
the three propositions, of which they con- 
sist, have been always expressed. But it 
often happens, that one of the premises is a 
truth, not only evident, but also familiar, 
and in the minds of all men ; in which case, 
it is generally omitted : and by this means 
we have an imperfect syllogism, which 
seems to be made up of only two proposi- 
tions. Should we, for instance, argue in 
this manner, 

God is our Creator^ 

Therefore he must be worshipped : 



115 

the syllogism appears to be imperfect, as 
consisting but of two propositions : yet it is, 
in reality, complete ; except that the major, 
Our Creator must be worshipped^ is omit- 
ted, and left to the reader to supply as a 
propositions so familiar and evident, that it 
cannot escape him. And these seemingly 
imperfect syllogisms are called enthy° 

MEMES. 

And here, as enthymemes are the only 
modes of reasoning which are in general 
use, it may not be improper to take some 
notice of their various forms. 

Sometimes the reasoning proposition, 
that is, the proposition expressed, as the 
foundation of the conclusion, is placed first; 
and the conclusion follows, with the sign of 
reasoning prefixed to it; as in the foregoing 
example : and this form constitutes, what, 



116 

for the sake of distinction, may be called 

the REGULAR ENTHYMEME. 

\ 

Another form, termed by a late writer* 
the OBVIOUS ENTHYMEME, resembling the 
preceding, but yet somewhat different from 
it, is, where the reasoning proposition is in 
like manner placed first, and the conclusion 
after it; but with the sign of reasoning pre- 
fixed, not to the latter, but to the former : for 
example^ 

Since for as J God is our Creator ^ 
He must be worshipped. 

A third form, which is termed the cau- 
sal ENTHYMEME, is that, in which the rea- 
soning proposition, with the sign of reason- 



^ Mr. Collard. 



117 

ing prefixed to it, follows the conclusion | 
thus, 

God must be worshipped ; 
Because he is our Creator.^ 



^ To these tlie writer, above aHuded to, has 
added a fourth, which he calls the HYPOXHEXiCAii 

ENTHYMEME ; aS, 

If God be our Creator ^ 
He must be worshipped 

Here, according to our author, there is a con- 
clusion gained, that God must be worshipped; found- 
ed on a supposition, which, though not express- 
ed, is understood, and supposed to be obvious^ 
naraely, that our creator must be worshipped: 
And, when this supposition is expressed, the act 
of reasoning will assume the form of a sj'Hogism, 
Thus, 

L S 



118 



But whatever be the form of the enthy- 
meme^ it will be easy for the reader to sup- 
ply what is wanting, and to convert any 



Our Creator must be worshipped ; 

If God be {that is, admit that God is) otir Crea- 
tor : 

{Jind you cannot but admits that) He must be 
worshipped. 

And this enthymeme, as he terms it, though it 
has hitherto been called, by all writers on the 
subject, a proposition, is, he contends, one of the 
most common, and, certainly one of the most 
useful, forms of reasoning in the compass of lan- 
guage. 

But, be this as it may, he very justly cautions 
us against supposing, that any two propositions, 
one taken conditionally and the other positively, 
will form an hypothetical enthymeme; which can- 



119 

such act of reasoning into a regular syllo- 
gism. For he has only to ask himself, 
upon what supposition the conclusion^ 
which is drawn from the reasoning propo- 
sition, depends ; and when this supposition, 
which is always an obvious one, is once 



not be, unless the attributes which should consti- 
tute the major and middle terms^ that is, unless 
the predicate of the conditional proposition and 
the predicate of the positive proposition, be such 
as universally agree, or universally disagree, with 
each other. These propositions, for example^ 

If I had leisure, 

I would dedicate much time to study, 

do not constitute an act of reasoning ; because it 
is not an universal fact, that every one, who has 
leisure, would, or would not, dedicate much time 
to study. 



120 

difsicoverecl, it will be tlie proposition omit- 
ted. For example, 

God is our Creator : 

Therefore he is to be worshipped. 

Upon what supposition does this conclnsion 
depend ? Evidently upon this ; that our 
Creator is to be worshipped Let this sup- 
position then be expressed, and the syllo- 
gism is complete. 

Our creator is to he worshipped : 

G(d is our Creator : 

Therefore God is to be worshipped. 



121 



But there is another species of reason- 
ing with two propositions, which seems to 
be complete in itself, and where we admit 
the conclusion without any tacit or suppos- 
ed judgment in the mind, from which it fol- 
lows syllogistically* This happens be- 
tween prop ^sitions where the connexion is 
such, that the admission of the one, neces- 
sarily, and at the first sight, implies the ad- 
mission of the other. For if it so happen, 
that the proposition on which the other de- 
pends is self-evident, we content ourselves 
with barely affirming it, and infer the other 
by a direct conclusion. Thus by admitting 
an universal proposition, we are forced also 
to admit of all the particular propositions 
comprehended under it, this being the very 



condition that constitutes a proposition uni- 
versal. If then, that univerisal proposition 
chances to be self-evident, the particular 
ones follow of course, without any farther 
train of reasoning. Whoever allov/s, for in- 
stance, that things equal to one and the 
same things are equal to one another^ must 
at the same time allow, that two triangles^ 
each equal to a square whose side is three 
inchesj are equal to one another. This ar- 
gument therefore^ 

Things equal to one and the same thing, 
are equal to one another ; 

Therefore thege two triangles, each 
equal to the square of a line of three inches, 
are equal to one another ; 

is complete in its kind, and contains all that 
is ne<essary towardj^ a just and legitimate 
conclusion. For the first or universal pro- 
position is self-evident, and therefore re- 



quires no farther proof. Anil as the truth 
of the particular is inseparably connected 
with that of the universal, it follows from 
it by an obvious and unavoidable conse- 
quence. 

Now in all cases of this kind, where 
propositions are deduced one from another 
on account of a known and evident connex- 
ion, we are said to rea^^on by immediate 
CONSEQUENCE. It is truc, that these argu- 
ments may be considered as enthymemes, 
who^e major propositions are wanting. — 
The argument, for instance, but just men- 
tioned, when represented according to this 
view will run as follows: 

1^ things equal to one and the same 
thins;, are equal to one another^ these two 
triangles, each equal to a square whose 
side is three inches^ are also equal to one 
another : 



But things equal to one and the same 
things are equal to one another : 

Therefore also these triangles^ Sfc. 
are equal to one another. 

But then it is peculiar to them, thtit the 
ground upon which the conclusion restS;, 
namely, its coherence with the minor, is of 
itself evident, and seems immediately to fol- 
low from the rules and reasons of iosrick. 
As it is therefore entirely unnecessary to ex- 
press a self-evident connexion, the major, 
whose office that is, is constantly omitted ; 
nay, and seems so very little needful to en- 
force the conclusion, as to be accounted no 
part of the argument. 



125 



Of Compound Syllogisms. 



A Compound Syllogism consists, as was 
before observed, of more than three propo- 
sitions, and may be resolved into two or 
more syllogisms. The chief of these are 
the EpiCHiREMA, Dilemma, Prosyllogism, 
Sorites, and Induction of particulars. 

Epichirema is a syllogism, in which we 
prove the major, or the minor, or both, be- 
fore we draw the conclusion : as, 

Sickness may be good for us ; because it 
brings us to consider our ways : 

But we are uneasy under sickness; as 
appears from our sighs^ groans^ and com- 
plaints: 



M 



126 

Therefore we are sometimes uneasy^ 
under what is good for us. 

A Dilemma is an argument, by which 
we endeavour to prove the absurdity or 
falsehood of some assertion. In order to 
this, we assume a conditional proposition, 
the antecedent of which is the assertion to 
be disproved, and the consequent a disjunc- 
tive proposition, enumerating all the possi- 
ble suppositions upon which that assertion 
can take place. If then it appear, that all 
these suppositions ought to be rejected, it is 
plain that the antecedent or assertion itself 
must be rejected also. When, therefore, 
such a proposition is made the major of any 
syllogism, if the minor rejects all the suppo- 
sitions contained in the consequent, it fol- 
lows necessarily, that the conclusion must 
reject the antecedent; which, as has been 
said, is the assertion to be disproved. — 



i27 

Hence it appears, that we may define a di^ 
lemma to be a conditional or hypothetical 
syllogism, where the consequent of the ma- 
jor is a disjunctive proposition, which is 
wholly taken away or removed in the minor. 
It follows, that a dilemma is an argument 
in the modus tollens of conditional syllo- 
gisms. And it is plain, that if the antece- 
dent of the major be an affirmative proposi^ 
tion, the conclusion will be negative ; but 
that, if it be a negative proposition, the con- 
clusion will be affirmative. 

The following is an example. 

If God did not create the world perfect 
in its kind ; it must have proceeded^ either 
from want of inclination^ or want of power : 
But it could not have proceeded^ either 
from want of inclination^ or want of power : 
Therefore it is absurb to say, that God 
did not create the world perfect in its kin^. 



128 

A dilemma may be faulty three ways, 
1. When what is affirmed or denied, in the 
minor, concerning the several suppositions 
in the consequent of the major, is false. 2. 
When all the possible suppositions upon 
which the assertion, contained in the ante- 
cedent, can take place, are not fully enu- 
merated in the consequent. 3. When the 
argument may be retorted with equal force 
against him who uses it.^ 



^ There was, says Dr. Watts, a famous an- 
cient instance of this case, w herein a dilemma was 
retorted. Euathlus promised Protagoras a re- 
ward when he had taught him the art of pleading;, 
and it was to be paid the first day that he gained 
any cause in the coui't. After a considerable 
time, Protagoras goes to law with Euathlus for 
the reward, and uses this dilemma. Either the 
cause will go on my side, or on yours : if the cause 
goes on my side^ you must pay me according to the 



129 

A Prosy llogism is a form of reasoning, 
in which two or more syllogisms are so 
connected together, that the conclusion of 
the former is the major or minor of tlie fol- 
lowing. 

Blood cannot think : 

But the soul of man thinks : 

Therefore the soul of man is not blood : 



sentence of the judge : if the cause goes on your side, 
you must pay me according to bargain : tlierefore 
whether the cause goes for me^ or against me, you 
must pay me the reward. But Eiiathlus retorted 
this dilemma, thus. Either 1 shall gain the cause, 
or lose it: if I gain the cause^ then nothing will be 
due to you according to the sentence oj the judge : 
and if Hose the cause, nothing -zvill be due to you, 
according to my bargain: therefore, whether I lose 
or gain the cause I will not pay you : for nothing 
will be due to you. 

WattsVs Lodck, part III. c. ii. s. 6. 
M 3 



130 

The soul of a brute is blood : 
Tlierefore the soul of man is different 
from the soul of a brute. 

A Sorites is a way of arguing, in which 
several propositions are so linked together 
that the predicate of one becomes continual- 
ly the subject of the next following : until 
at last a conclusion is formed, by bringing 
together the subject of the first proposition, 
and the predicate of the last ; as in the follow- 
ing example.^ 

There can be no enjoyment of pro'perty^ 
without government : 

J^o government^ without a magistrate : 
tTVb magistrate, without obedience : 



^ Themistocles, it is said, was sometimes 
wont to use this form of reasoning, when, in the 
way of pleasantry, he was disposed to speak of, 



131 

Jlnd no obedience^ where every one acts as 
he pleases : 

Therefore^ there can be no enjoyment of 
property where every one acts as he 
pleases. 

Reasoning by Induction, is when we 
infer universally concerning any idea, what 
we have before affirmed or denied, sepa- 
rately, of all its several parts or subdivi- 
sions. Thus, if we suppose the whole race 



and exaggerate the influence of his son, who was 
then a child : 

My son governs his mother : 

His mother governs me : 

I govern Mhens : 

Athens governs Greece : 

Greece governs the world : 

Therefore my son governs the world. 



13^ 

of animals subdivided into men, beasts, 
birds, insects, and fishes, and then reason 
concerning them in this manner — All men 
have the power of beginning motion ; all 
leasts have this power ; all birds ; all in- 
sects ; all fishes : therefore all animals have 
the power of beginning motion — the argu- 
ment is an Induction. The truth of the 
conclusion, in this way of reasoning, de- 
pends upon the parts and subdivisions being 
4ully enumerated. 



To this cbapier, which treats of various 
kinds of ^^llogisms, it may not be improper 
to add some account of several sorts of ar- 
guments, which are usually distinguished hy 
Latin names. For as these names will oc- 
cajbioually occur in books and in conveisa- 



133 

tioo, it will be of use to understand what is 
meant by them. 

Demonstrations A priori are those which 
prove the effect from the cause : as, The 
scripture is infallible ; because it is the 
word of Godf who cannot lie. Demonstra- 
tions A POSTERIORI^ on the contrary^ are those 
which prove the cause from the effect : as, 
till the works of God ars useful and well 
contrived: therefore the Creator is wise 
and good. 

The ARGUMENTUM DUCENS IN ABSUR- 

DUM has been already explained. We 
shall only add, that it is sometimes called 
REDUCTio AD ABSURDUM, and a proof PER 

IMPOSSIBILE. 

When we infer, that a certain proposi- 
tion is true, because another has been prov- 
ed to be true, which is less probable, this is 



134 

called au argument ex minus probabili 

AD MAGIS. 

Wlien we argue from the certainty of a 
thing in the same circumstances, we are 
said to argue ex pari. 

When we prove the truth of any propo- 
sition upon whicli, if proved, our opponent 
had agreed to admit th6 truth of the propo- 
sition in question, this is an argument ex 

CONCESSO. 

When an argument is taken from the 
nature of things and addressed to the reason 
of mankind, it is called argumentum ad 

JUDICIUM. 

When it is borrowed from some con- 
vincing testimony, it is argumentum ad fi 

DEM. 



135 

When it is drawn from any insufficient 
meflium whatsoever, in confidence that our 
opponent has not skill to refute or answer it^ 

this is ARGUMENTUM AD XGNORANTIAM. 

When we prove a thing to be true, or 
false, from the professed opinion of the per- 
son with whom we dispute, it is named 

ARGUMENTUM AD HOMlNfcM. 

When the argument is brought from the 
sentiments of some wise, grave, or good 
men, whose authority we reverence and 
hardly dare oppose, it is called argumen- 

TUM AD VERECUNDIAM, Or AD MODESTIAM. 

When we expose a man to hatred by al- 
leging that his opinion has been held by 
some heretics or wicked men, calling him 
a Socinian, a Jacobin, or the like, it is ar- 

GUMEMTUM AB INVIDIA DEDUCTUM. 



136 

And, lastly, when an argument is bor- 
rowed from any topics, which are suited 
to engage the inclinations or passions of the 
hearers on the side of the speaker, rather 
than to convince their judgments, this is 
ARGUMENTUM AD PASSioNES, or, if it be made 

publicly AD POPULUM. 



137 



CHAPTER IlL 



Of Sophisms. 



Sophisms are false arguments, which 
have the appearance of being true. 

The most remarkable of them are reduced 
by Logicians to the following heads. 

1. Ignorantia elenchi^ or a mistake 
of the question. As if, the question being 
put, whether excess of wine he hurtful to 
those who indulge in it, any one should ar- 
gue, that wine revives the spirits^ gives a 
man courage, and makes him more strong 
and active; and then take it for granted, 

that the point in debate is fully determined. 

N 



138 

But what;, it might be answered^ is all this 
to the purpose ? Wine, taken in moderation 
may have all these good effects which you 
ascribe to it; but the question is not, what 
are the effects of wine taken in moderation, 
but what are the effects of it when taken to 
excess. 

S. Petitio principii, or a supposition 
of what is not granted ; as^ 

There is no salvation out of the church: 
Protestants are out of the church : 
Therefore^ Protestants cannot he saved. 

The minor is here taken for granted, 
which is by no means to be allowed. 

3. A CIRCLE is, when we prove one of 
the premises by the conclusion. 

As if one were to reason thus : 



139 

The church being infallible^ what she 
testijies must be believed : 

But the church testifies^ that the scrip- 
tures are the word of God : 

Therefore ythat the scriptures are the word 
of God J must be believed. 

— and, on being asked how it appears that 
the church is infallible^ should undertake to 
prove it;, as follows : 

The scriptures being the word of God^ 
what they teach must be believed : 

But the scriptures teach us^ that the 
church is infallible : 

Therefore that the church is infallible^ 
must be believed. 

In this way we might prove any thing. 

4. NoN CAUSA PRO CAUSA, or the assig. 
nation of a false canse : as if any one, when 



140 

an infectious disease is imported into a city, 
should impute tlie misfortune to the anger of 
God. 

5. Fallacia accidentis ; when we ar- 
gue from what is true by accident, to what 
is true in the nature of things. So if opium, 
or the Peruvian bark, has been used impru- 
dently, or unsuccessfully, so as to do injury ; 
some absolutely pronounce against the use 
of the bark, or of opium, on all occasions, 
and are ready to call them poisons. 

6. The next sophism borders on the 
former; and is, when we argue from that 
which is true in particular circumstances, to 
prove the same thing true simply, that is, 
abstractedly from all circumstances: this is 
called, in tlie schools, a sophism a dicto 

SECUNDUM QUID, AD DICTUM SIMPLICITER J 

as, 



141 

That which is bought in the shambles is 
eaten for dinner : 

Maw meat is bought in the shambles ; 
Therefore raw meat is eaten for dinner. 

This sort of sophism has its reverse, 
when we argue a dicto simpliciter ad 
DICTUM SECUNDUM QUID ; 01% to express it in 
English, from that which is true simply, or 
abstractedly from particular circumstances, 
to prove the same thing true when attended 
with such circumstances: as if a traitor 
should ar-ue from the sixth commandmentj 
Thou shalt not kill^ to prove that he himself 
ought not to be hanged. 

7. There are also sophisms of composi- 
tion and DIVISION. 

A sophism of composition is, when we 
infer any thing concerning ideas in a com» 

N3 



14^ 

pounded sense^ which is only true in a divi^ 
ded sense ; aS; 

Two and three are even and odd ; 
Five are two and three ; 
Therefore jive is even and odd. 

A sophism of division is, when we infer 
the same thing concerning ideas in a divided 
sense, which is only true in a compound 
sense. As^ 

Five is one number ; 
Two and three are five ; 
Therefore two and three are one num- 
her. 

Lastly, sophisms arise also from the am- 
biguity of words ; and indeed several of the 
former fallacies might be reduced to this 
head. As if one should argue thus^^ 



143 



Jl church is a building of stone; 
Jl religious asufembly is a church ; 
Therefore a religious assembly is a build- 
ing of stone. 



il4 



Besides the special description of true 
syllo2;isms and sophisms already given, and 
the rules by which the one are formed and 
the other refused ; there are these two gene- 
ral methods of reducing all syllogisms what- 
ever to a te&t of their truth or falsehood. 

1. One of the premises must contain the 
conclusion^ and the other must show that 
the conclusion is contained in it. 

For the illustration of this, let us take 
the foUowing example : 

Whosoever is a slave to his natural in- 
clinations is miserable; 



145 

A wicked man is a slave to his natural 
inclinations ; 

Therefore a wicked man is miserable. 

Here it is evident, that the major propo- 
position contains the conclusion ; for under 
the general character of a slave to natural 
inclinations^ a wicked man is contained or 
included; and the minor proposition de- 
Clares it : whence a conclusion is evidently 
deduced that the wicked man is miserable. 

3. As the terms in every syllogism are 
usually repeated twice, so they must ^e 
taken precisely in the same sense in both 
places. 

For the greater part of the mistakes, 
which arise in forming sylloi^isms, is deriv- 
ed from some little difference in the sense of 
one of the terms in the two parts of the syh 
logism wherein it is used. 



146 

It is a sin to Mil a man ; 

Jl murderer is a man ; 

Therefore it is a sin to kill a murderer. 

Here the word kill in the first proposi- 
tion signifies to kill unjustly^ or without 
law ; in the conclusion^ it is taken absolute- 
ly for putting a man to death in general; and 
therefore the inference is not good. 

What I am is a man ; 
Ton are not what I am ; 
Therefore you are not a man. 

Here, what I am^ in the major proposi- 
tion^ U takin specially^ for my nature ; but, 
in the minor proposition, the same words 
are taken individually, for my person : 
therefore the inference must he false ; for the 
syllogism does not take the term what I am 
both times in the same sense. 



147 

He who says you are an animal^ says 
true : 

But he who says you are a goose^ says^ 
you are an animal : 

Therefore he^ who says^ you are a goose 
says true. 

Iq the major proposition the word ani- 
mal is the predicate of an incidental propo- 
sition ; which incidental proposition being 
afBrmative^ renders the predicate of it parti- 
cular, according to the third axiom. And 
consequently the word animal there, signi- 
fies only human animality. In the minor 
proposition the word animal for the same 
reason signifies the animality of a goose; 
therefore it becomes an ambiguous term^ 
and unfit to build a conclusion upon. 



148 



PART IV, 



Of Method. 



We have now done with the three first 
operations of the mind. There is yet a 
fourth, which regards the disposal and ar- 
rangement of our thoughts in such a manner 
as that their mutual connexion and depen- 
dence may be clearly seen ; and this is what 
logicians call method. 

In unfolding any part of human know- 
ledge, the relations of things do not always 
immediately appear, upon romparing them 
with one another. Hence we jiave recourse 
to intermediate ideas, and hy means of them 
are furnished with those previous proposi- 



149 

tions that lead to the conclusion we are in 
quest of. And if it so happen, that the pre- 
vious propositions themselves are not suffi« 
ciently evident, we endeavour by new mid- 
die terms to ascertain their truth ; still tra- 
cing things backward, in a continued series, 
until at length we arrive at some syllogism 
where the premises are first and self-evident 
principles. This done, we become perfect- 
ly satisfied as to the truth of all the conclu- 
sions we have passed through, inasmuch as 
they are now seen to stand upon the firm 
and immoveable foundation of our intuitive 
perceptions. And as we arrived at this cer- 
tainty by tracing our conclusions backward 
to the original principles from which they 
are deduced ; so we may at any time renew 
it by a direct contrary process, if, beginning 
with these principles, we carry the train of 
our thoughts forward, until they lead us, by 
a connected chain of proofs, to the very last 

conclusion of the series. 

O 



ISO 

Hence it appears, that, in disposing and 
putting together our thoughts (either for our 
own use, — that the discoveries which we 
have made may at all times be open to the 
review of our minds ; or for the communi- 
cating or unfolding of these discoveries to 
others,) there are two ways of proceeding, 
equally within our choice. For we may so 
propose the truths relating to any part of 
knowledge, as they presented themselves to 
the mind in the manner of investigation ; 
carrying on the series of proofs in a reverse 
order, until they at last terminate in first 
principles : or beginning with these princi- 
pies, we may take the contrary way ; and 
from them deduce, by a direct train of rea- 
soning, all the several propositions we want 
to establish. This diversity, in the manner 
of arranging our thoughts, gives rise to the 
two-fold division of method established by 
logicians. For method, according to their 
use of the word, is nothing else than the or- 



151 

der and disposition of our thoughts relating 
to any subject. When truths are so dispos. 
ed and put together, as they were or mi^^ht 
have been discovered, this is called the 

ANALYTICK METHOD, Or the METHOD OF 

RESOLUTION ; inasniuch as it traces things 
backward to their source, and resolves 
knowledge into its first and original princi- 
ples. When, on the other hand, truths are 
deduced from these first principles, and con- 
nected according to their mutual dependence* 
so that the truths first in order tend always 
to the demonstration of those uhicli follow, 
this constitutes what we call the synthetick 

METHOD or METHOD OF COMPOSITION. The 

first of these has also obtained the name of 
the METHOD OF INVENTION ; becausc it ob- 
serves the order in which our thoughts sue 
ceed one another in the invention or disco- 
very of truth : the , other again is often de- 
nominated the method of science ; inas- 



152 



much as, in laying our thoughts before 
others, we generally choose to proceed iu 
the synthetick manner, deducing them from 
their first principles. 



THE END, 



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